Partial port hybrid csi feedback for mimo wireless communication systems

ABSTRACT

The method comprises receiving periodic CSI feedback configuration information including a periodicity value and an offset value corresponding to a first CSI report, and at least one periodicity value and at least one offset value corresponding to a second CSI report, measuring a first CSI reference signal (CSI-RS) and a second CSI-RS configured for a periodic CSI reporting based on at least two different enhanced MIMO types (eMIMO-Types), generating the first CSI report and the second CSI report for the first eMIMO-Type and the second eMIMO-Type, respectively, determining a periodic reporting interval for each of the first CSI report and the second CSI report, and reporting the first and second CSI reports based on the determined periodic reporting intervals using a physical uplink control channel (PUCCH) format 2 or a PUCCH format 3 or a combination of the PUCCH format 2 and the PUCCH format 3.

CROSS-REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 62/301,823, filed on Mar. 1, 2016, entitled“Partial Port Hybrid CSI Feedback for MIMO Wireless CommunicationSystems;” U.S. Provisional Patent Application Ser. No. 62/320,717, filedon Apr. 11, 2016, entitled “Partial Port Hybrid CSI Feedback for MIMOWireless Communication Systems;” U.S. Provisional Patent ApplicationSer. No. 62/376,773, filed on Aug. 18, 2016, entitled “Hybrid CSIReporting on PUCCH for MIMO Wireless Communication Systems;” and U.S.Provisional Patent Application Ser. No. 62/382,342, filed on Sep. 1,2016, entitled “Partial Port Hybrid CSI Feedback for MIMO WirelessCommunication Systems.” The content of the above-identified patentdocuments are incorporated herein by reference.

TECHNICAL FIELD

The present application relates generally to uplink reporting operationin wireless communication systems. More specifically, this disclosurerelates to hybrid channel state information (CSI) feedback on a physicaluplink control channel (PUCCH) for MIMO Wireless Communication Systems.

BACKGROUND

Understanding and correctly estimating the channel in an advancewireless communication system between a user equipment (UE) and an eNodeB (eNB) is important for efficient and effective wireless communication.In order to correctly estimate the channel conditions, the UE willreport (e.g., feedback) information about channel measurement, e.g.,CSI, to the eNB. With this information about the channel, the eNB isable to select appropriate communication parameters to efficiently andeffectively perform wireless data communication with the UE. However,with increase in the numbers of antennas and channel paths of wirelesscommunication devices, so too has the amount of feedback increased thatmay be needed to ideally estimate the channel. This additionally-desiredchannel feedback may create additional overheads, thus reducing theefficiency of the wireless communication, for example, decrease the datarate.

SUMMARY

The present disclosure relates to a pre-5^(th)-Generation (5G) or 5Gcommunication system to be provided for supporting higher data ratesbeyond 4-Generation (4G) communication system such as Long TermEvolution (LTE). Embodiments of the present disclosure provide a hybridCSI reporting on PUCCH for MIMO wireless communication systems.

In one embodiment, a user equipment (UE) for communicating in amulti-input multi-output (MIMO) wireless communication system isprovided. The UE includes a transceiver configured to receive, from aneNodeB (eNB), periodic CSI feedback configuration information includinga periodicity value and an offset value corresponding to a first CSIreport, and at least one periodicity value and at least one offset valuecorresponding to a second CSI report. The UE further includes at leastone processor configured to measure a first CSI reference signal(CSI-RS) and a second CSI-RS configured for a periodic CSI reportingbased on at least two different enhanced MIMO types (eMIMO-Types), theat least two different eMIMO-Types comprising a first eMIMO-Type and asecond eMIMO-Type that are configured with at least two differentantenna port configurations, respectively; generate the first CSI reportand the second CSI report for the first eMIMO-Type and the secondeMIMO-Type, respectively, using respective codebooks for the firsteMIMO-Type and the second eMIMO-Type, the first CSI report and thesecond CSI report being associated with the first CSI-RS and the secondCSI-RS, respectively; determine a periodic reporting interval for eachof the first CSI report and the second CSI report, wherein the periodicreporting interval for the first CSI report is determined based on atleast one of the periodicity value or the offset value corresponding tothe first CSI report, and at least one periodicity value and at leastone offset value corresponding to the second CSI report; and report thefirst and second CSI reports based on the determined periodic reportingintervals using a physical uplink control channel (PUCCH) format 2 or aPUCCH format 3 or a combination of the PUCCH format 2 and the PUCCHformat 3.

In another embodiment, an eNodeB (eNB) for communicating in amulti-input multi-output (MIMO) wireless communication system isprovided. The eNB includes at least one processor configured todetermine a first CSI reference signal (CSI-RS) and a second CSI-RSconfigured for a periodic CSI reporting based on at least two differentenhanced MIMO types (eMIMO-Types), the at least two differenteMIMO-Types comprising a first eMIMO-Type and a second eMIMO-Type thatare configured with at least two different antenna port configurations,respectively; and determine a periodic reporting interval for each of afirst CSI report and a second CSI report, wherein the periodic reportinginterval for the first CSI report is determined based on at least one ofa periodicity value or an offset value corresponding to the first CSIreport, and at least one periodicity value and at least one offset valuecorresponding to the second CSI report. The eNB further includes atransceiver configured to transmit, to user equipment (UE), periodic CSIfeedback configuration information including a periodicity value and anoffset value corresponding to a first CSI report, and at least oneperiodicity value and at least one offset value corresponding to asecond CSI report; and receive, from the UE, the first and second CSIreports based on the determined periodic reporting intervals using aphysical uplink control channel (PUCCH) format 2 or a PUCCH format 3 ora combination of the PUCCH format 2 and the PUCCH format 3, wherein thefirst CSI report and the second CSI report are generated for the firsteMIMO-Type and the second eMIMO-Type, respectively, using respectivecodebooks for the first eMIMO-Type and the second eMIMO-Type, the firstCSI report and the second CSI report being associated with the firstCSI-RS and the second CSI-RS, respectively. In yet another embodiment, amethod for communicating in a multi-input multi-output (MIMO) wirelesscommunication system is provided. The method comprising receiving, froman eNodeB (eNB), periodic CSI feedback configuration informationincluding a periodicity value and an offset value corresponding to afirst CSI report, and at least one periodicity value and at least oneoffset value corresponding to a second CSI report; measuring a first CSIreference signal (CSI-RS) and a second CSI-RS configured for a periodicCSI reporting based on at least two different enhanced MIMO types(eMIMO-Types), the at least two different eMIMO-Types comprising a firsteMIMO-Type and a second eMIMO-Type that are configured with at least twodifferent antenna port configurations, respectively; generating thefirst CSI report and the second CSI report for the first eMIMO-Type andthe second eMIMO-Type, respectively, using respective codebooks for thefirst eMIMO-Type and the second eMIMO-Type, the first CSI report and thesecond CSI report being associated with the first CSI-RS and the secondCSI-RS, respectively; determining a periodic reporting interval for eachof the first CSI report and the second CSI report, wherein the periodicreporting interval for the first CSI report is determined based on atleast one of the periodicity value or the offset value corresponding tothe first CSI report, and at least one periodicity value and at leastone offset value corresponding to the second CSI report; and reportingthe first and second CSI reports based on the determined periodicreporting intervals using a physical uplink control channel (PUCCH)format 2 or a PUCCH format 3 or a combination of the PUCCH format 2 andthe PUCCH format 3.

Other technical features may be readily apparent to one skilled in theart from the following figures, descriptions, and claims.

Before undertaking the DETAILED DESCRIPTION below, it may beadvantageous to set forth definitions of certain words and phrases usedthroughout this patent document. The term “couple” and its derivativesrefer to any direct or indirect communication between two or moreelements, whether or not those elements are in physical contact with oneanother. The terms “transmit,” “receive,” and “communicate,” as well asderivatives thereof, encompass both direct and indirect communication.The terms “include” and “comprise,” as well as derivatives thereof, meaninclusion without limitation. The term “or” is inclusive, meaningand/or. The phrase “associated with,” as well as derivatives thereof,means to include, be included within, interconnect with, contain, becontained within, connect to or with, couple to or with, be communicablewith, cooperate with, interleave, juxtapose, be proximate to, be boundto or with, have, have a property of, have a relationship to or with, orthe like. The term “controller” means any device, system or part thereofthat controls at least one operation. Such a controller may beimplemented in hardware or a combination of hardware and software and/orfirmware. The functionality associated with any particular controllermay be centralized or distributed, whether locally or remotely. Thephrase “at least one of,” when used with a list of items, means thatdifferent combinations of one or more of the listed items may be used,and only one item in the list may be needed. For example, “at least oneof: A, B, and C” includes any of the following combinations: A, B, C, Aand B, A and C, B and C, and A and B and C.

Moreover, various functions described below can be implemented orsupported by one or more computer programs, each of which is formed fromcomputer readable program code and embodied in a computer readablemedium. The terms “application” and “program” refer to one or morecomputer programs, software components, sets of instructions,procedures, functions, objects, classes, instances, related data, or aportion thereof adapted for implementation in a suitable computerreadable program code. The phrase “computer readable program code”includes any type of computer code, including source code, object code,and executable code. The phrase “computer readable medium” includes anytype of medium capable of being accessed by a computer, such as readonly memory (ROM), random access memory (RAM), a hard disk drive, acompact disc (CD), a digital video disc (DVD), or any other type ofmemory. A “non-transitory” computer readable medium excludes wired,wireless, optical, or other communication links that transporttransitory electrical or other signals. A non-transitory computerreadable medium includes media where data can be permanently stored andmedia where data can be stored and later overwritten, such as arewritable optical disc or an erasable memory device.

Definitions for other certain words and phrases are provided throughoutthis patent document. Those of ordinary skill in the art shouldunderstand that in many if not most instances, such definitions apply toprior as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following description taken inconjunction with the accompanying drawings, in which like referencenumerals represent like parts:

FIG. 1 illustrates an example wireless network according to embodimentsof the present disclosure;

FIG. 2 illustrates an example eNodeB (eNB) according to embodiments ofthe present disclosure;

FIG. 3 illustrates an example user equipment (UE) according toembodiments of the present disclosure;

FIG. 4A illustrates a high-level diagram of an orthogonal frequencydivision multiple access transmit path according to embodiments of thepresent disclosure;

FIG. 4B illustrates a high-level diagram of an orthogonal frequencydivision multiple access receive path according to embodiments of thepresent disclosure;

FIG. 5 illustrates an example structure for a downlink (DL) subframeaccording to embodiments of the present disclosure;

FIG. 6 illustrates an example transmission structure of an uplink (UL)subframe according to embodiments of the present disclosure;

FIG. 7 illustrates an example transmitter block diagram for a physicaldownlink shared channel (PDSCH) subframe according to embodiments of thepresent disclosure;

FIG. 8 illustrates an example receiver block diagram for a PDSCHsubframe according to embodiments of the present disclosure;

FIG. 9 illustrates an example transmitter block diagram for a physicaluplink shared channel (PUSCH) subframe according to embodiments of thepresent disclosure;

FIG. 10 illustrates an example receiver block diagram for a PUSCH in asubframe according to embodiments of the present disclosure;

FIG. 11 illustrates an example configuration of a two dimensional (2D)array according to embodiments of the present disclosure;

FIG. 12 illustrates an example dual-polarized antenna port layouts for{2, 4, 8, 12, 16} ports according to embodiments of the presentdisclosure;

FIG. 13 illustrates an example dual-polarized antenna port layouts for{20, 24, 28, 32} ports according to embodiments of the presentdisclosure;

FIG. 14 illustrates an example Class A channel state information (CSI)feedback scheme according to embodiments of the present disclosure;

FIG. 15 illustrates an example Class B CSI feedback scheme according toembodiments of the present disclosure;

FIG. 16 illustrates an example dual-polarized antenna port layouts for{24, 48, 96} ports according to embodiments of the present disclosure;

FIG. 17 illustrates an example dual-polarized antenna port layouts for{32, 64, 128} ports according to embodiments of the present disclosure;

FIG. 18 illustrates an example full port hybrid CSI feedback scheme (Alt0) according to embodiments of the present disclosure;

FIG. 19 illustrates an example partial port hybrid CSI feedback scheme(Alt 1) according to embodiments of the present disclosure;

FIG. 20 illustrates another example partial port hybrid CSI feedbackscheme (Alt 2) according to embodiments of the present disclosure;

FIG. 21 illustrates an example hybrid PMI pre-coder (Alt 1-1 and Alt 2)according to embodiments of the present disclosure;

FIG. 22 illustrates an example subarray based hybrid CSI feedback schemeaccording to embodiments of the present disclosure;

FIG. 23 illustrates an example subarray types according to embodimentsof the present disclosure;

FIG. 24 illustrates an example subarray cycling at an eNB according toembodiments of the present disclosure;

FIG. 25 illustrates an example millimeter wave communication system withhybrid beam forming (HBF) according to embodiments of the presentdisclosure;

FIG. 26 illustrates an example hybrid CSI feedback framework formillimeter wave communication system according to embodiments of thepresent disclosure;

FIG. 27 illustrates an example UE-transparent eNB and UE proceduresaccording to embodiments of the present disclosure;

FIG. 28 illustrates an example UE-non-transparent eNB and UE procedures(Alt 0) according to embodiments of the present disclosure;

FIG. 29 illustrates another example UE-non-transparent eNB and UEprocedures (Alt 1) according to embodiments of the present disclosure;

FIG. 30 illustrates yet another example UE-non-transparent eNB and UEprocedures (Alt 2) according to embodiments of the present disclosure;and

FIG. 31 illustrates an example physical uplink control channel (PUCCH)Format 3a/3b for simultaneous CSI and hybrid automatic repeat request(HARQ) acknowledgement/negative acknowledgement (ACK/NACK) transmissionaccording to embodiments of the present disclosure.

DETAILED DESCRIPTION

FIG. 1 through FIG. 31, discussed below, and the various embodimentsused to describe the principles of the present disclosure in this patentdocument are by way of illustration only and should not be construed inany way to limit the scope of the disclosure. Those skilled in the artwill understand that the principles of the present disclosure may beimplemented in any suitably arranged system or device.

The following documents and standards descriptions are herebyincorporated by reference into the present disclosure as if fully setforth herein: 3GPP TS 36.211 v13.0.0, “E-UTRA, Physical channels andmodulation” (REF1); 3GPP TS 36.212 v13.0.0, “E-UTRA, Multiplexing andChannel coding” (REF2); 3GPP TS 36.213 v13.0.0, “E-UTRA, Physical LayerProcedures” (REF3); 3GPP TS 36.321 v13.0.0, “E-UTRA, Medium AccessControl (MAC) protocol specification” (REF4); 3GPP TS 36.331 v13.0.0,“E-UTRA, Radio Resource Control (RRC) protocol specification” (REF5).

To meet the demand for wireless data traffic having increased sincedeployment of 4G communication systems, efforts have been made todevelop an improved 5G or pre-5G communication system. Therefore, the 5Gor pre-5G communication system is also called a ‘Beyond 4G Network’ or a‘Post LTE System’.

The 5G communication system is considered to be implemented in higherfrequency (mmWave) bands, e.g., 60 GHz bands, so as to accomplish higherdata rates. To decrease propagation loss of the radio waves and increasethe transmission coverage, the beamforming, massive multiple-inputmultiple-output (MIMO), full dimensional MIMO (FD-MIMO), array antenna,an analog beam forming, large scale antenna techniques and the like arediscussed in 5G communication systems.

In addition, in 5G communication systems, development for system networkimprovement is under way based on advanced small cells, cloud radioaccess networks (RANs), ultra-dense networks, device-to-device (D2D)communication, wireless backhaul communication, moving network,cooperative communication, coordinated multi-points (CoMP) transmissionand reception, interference mitigation and cancellation and the like.

In the 5G system, hybrid frequency shift keying and quadrature amplitudemodulation (FQAM) and sliding window superposition coding (SWSC) as anadaptive modulation and coding (AMC) technique, and filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse codemultiple access (SCMA) as an advanced access technology have beendeveloped.

FIGS. 1-4B below describe various embodiments implemented in wirelesscommunications systems and with the use of OFDM or OFDMA communicationtechniques. The descriptions of FIGS. 1-3 are not meant to implyphysical or architectural limitations to the manner in which differentembodiments may be implemented. Different embodiments of the presentdisclosure may be implemented in any suitably-arranged communicationssystem.

FIG. 1 illustrates an example wireless network 100 according toembodiments of the present disclosure. The embodiment of the wirelessnetwork 100 shown in FIG. 1 is for illustration only. Other embodimentsof the wireless network 100 could be used without departing from thescope of this disclosure.

As shown in FIG. 1, the wireless network 100 includes an eNB 101, an eNB102, and an eNB 103. The eNB 101 communicates with the eNB 102 and theeNB 103. The eNB 101 also communicates with at least one network 130,such as the Internet, a proprietary Internet Protocol (IP) network, orother data network.

The eNB 102 provides wireless broadband access to the network 130 for afirst plurality of user equipments (UEs) within a coverage area 120 ofthe eNB 102. The first plurality of UEs includes a UE 111, which may belocated in a small business (SB); a UE 112, which may be located in anenterprise (E); a UE 113, which may be located in a WiFi hotspot (HS); aUE 114, which may be located in a first residence (R); a UE 115, whichmay be located in a second residence (R); and a UE 116, which may be amobile device (M), such as a cell phone, a wireless laptop, a wirelessPDA, or the like. The eNB 103 provides wireless broadband access to thenetwork 130 for a second plurality of UEs within a coverage area 125 ofthe eNB 103. The second plurality of UEs includes the UE 115 and the UE116. In some embodiments, one or more of the eNBs 101-103 maycommunicate with each other and with the UEs 111-116 using 5G, LTE,LTE-A, WiMAX, WiFi, or other wireless communication techniques.

Depending on the network type, other well-known terms may be usedinstead of “eNodeB” or “eNB,” such as “base station” or “access point.”For the sake of convenience, the terms “eNodeB” and “eNB” are used inthis patent document to refer to network infrastructure components thatprovide wireless access to remote terminals. Also, depending on thenetwork type, other well-known terms may be used instead of “userequipment” or “UE,” such as “mobile station,” “subscriber station,”“remote terminal,” “wireless terminal,” or “user device.” For the sakeof convenience, the terms “user equipment” and “UE” are used in thispatent document to refer to remote wireless equipment that wirelesslyaccesses an eNB, whether the UE is a mobile device (such as a mobiletelephone or smartphone) or is normally considered a stationary device(such as a desktop computer or vending machine).

Dotted lines show the approximate extents of the coverage areas 120 and125, which are shown as approximately circular for the purposes ofillustration and explanation only. It should be clearly understood thatthe coverage areas associated with eNBs, such as the coverage areas 120and 125, may have other shapes, including irregular shapes, dependingupon the configuration of the eNBs and variations in the radioenvironment associated with natural and man-made obstructions.

As described in more detail below, one or more of the UEs 111-116include circuitry, programming, or a combination thereof, for efficientCSI reporting on PUCCH in an advanced wireless communication system. Incertain embodiments, and one or more of the eNBs 101-103 includescircuitry, programming, or a combination thereof, for receivingefficient CSI reporting on PUCCH in an advanced wireless communicationsystem.

Although FIG. 1 illustrates one example of a wireless network 100,various changes may be made to FIG. 1. For example, the wireless network100 could include any number of eNBs and any number of UEs in anysuitable arrangement. Also, the eNB 101 could communicate directly withany number of UEs and provide those UEs with wireless broadband accessto the network 130. Similarly, each eNB 102-103 could communicatedirectly with the network 130 and provide UEs with direct wirelessbroadband access to the network 130. Further, the eNBs 101, 102, and/or103 could provide access to other or additional external networks, suchas external telephone networks or other types of data networks.

FIG. 2 illustrates an example eNB 102 according to embodiments of thepresent disclosure. The embodiment of the eNB 102 illustrated in FIG. 2is for illustration only, and the eNBs 101 and 103 of FIG. 1 could havethe same or similar configuration. However, eNBs come in a wide varietyof configurations, and FIG. 2 does not limit the scope of thisdisclosure to any particular implementation of an eNB.

As shown in FIG. 2, the eNB 102 includes multiple antennas 205 a-205 n,multiple RF transceivers 210 a-210 n, transmit (TX) processing circuitry215, and receive (RX) processing circuitry 220. The eNB 102 alsoincludes a controller/processor 225, a memory 230, and a backhaul ornetwork interface 235.

The RF transceivers 210 a-210 n receive, from the antennas 205 a-205 n,incoming RF signals, such as signals transmitted by UEs in the network100. The RF transceivers 210 a-210 n down-convert the incoming RFsignals to generate IF or baseband signals. The IF or baseband signalsare sent to the RX processing circuitry 220, which generates processedbaseband signals by filtering, decoding, and/or digitizing the basebandor IF signals. The RX processing circuitry 220 transmits the processedbaseband signals to the controller/processor 225 for further processing.

In some embodiments, the RF transceivers 210 a-210 n are capable oftransmitting, to user equipment (UE), periodic CSI feedbackconfiguration information including a periodicity value and an offsetvalue corresponding to a first CSI report, and at least one periodicityvalue and at least one offset value corresponding to a second CSIreport; and receiving, from the UE, the first and second CSI reportsbased on the determined periodic reporting intervals using a physicaluplink control channel (PUCCH) format 2 or a PUCCH format 3 or acombination of the PUCCH format 2 and the PUCCH format 3, wherein thefirst CSI report and the second CSI report are generated for the firsteMIMO-Type and the second eMIMO-Type, respectively, the first CSI reportand the second CSI report being associated with the first CSI-RS and thesecond CSI-RS, respectively.

In some embodiments, the RF transceivers 210 a-210 n are capable ofreceiving the first CSI report associated with the first eMIMO-Type,wherein the first CSI report includes at least one of a first precodingmatrix index (PMI) or a first rank indicator (RI), and wherein the firstPMI comprises at least one of a single PMI or a pair of two PMIs and thefirst eMIMO-Type is Class A; and receiving the second CSI reportassociated with the second eMIMO-Type, wherein the second CSI reportincludes at least one of a second PMI, a second RI, or a channel qualityindicator (CQI), and wherein and the second eMIMO-Type is Class B withK=1 resource.

In some embodiments, the RF transceivers 210 a-210 n are capable ofjointly receiving at least one of a first PMI or a first RI that isincluded in the first CSI report; and receiving each of the first andsecond CSI reports based on the determined periodic reporting intervalusing the PUCCH format, wherein the determined periodic reportinginterval of the first CSI report is determined based on at least one ofthe periodicity value M_(PMI/RI) or the offset value N_(OFFSET,PMI/RI)included in the periodic CSI feedback configuration information, whereinthe periodicity value M_(PMI/RI) is determined based on at least one ofthe periodicity values M_(RI) and N_(pd) for the second RI, or CQI,respectively, and wherein the offset value N_(OFFSET,PMI/RI) isdetermined based on at least one of the offset values N_(OFFSET,CQI) andN_(OFFSET,RI) for the CQI or the second RI, respectively.

In some embodiments, the RF transceivers 210 a-210 n are capable ofjointly receiving wideband first PMI and first RI included in the firstCSI report in subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,PMI/RI))mod(n_(pd)·M_(RI)·M_(PMI/RI))=0if a number of antenna ports associated with the second eMIMO-Type ismore than 1 and(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,PMI/RI))mod(N_(pd)·M_(PMI/RI))=0if the number of antenna ports associated with the second eMIMO-Type is1.

In some embodiments, the RF transceivers 210 a-210 n are capable ofseparately receiving first PMI and first RI that are included in thefirst CSI report; and receiving each of the first and second CSI reportsbased on the determined periodic reporting interval using the PUCCHformat, wherein each of the periodic reporting intervals for first PMIand a first RI, respectively, is determined based on the at least one ofthe periodicity value or the offset value included in the periodic CSIfeedback configuration information, wherein each of the periodicityvalues for the first PMI and the first RI, respectively, is determinedeither based on one another or at least one of the second RI or CQI, andwherein each of the offset values for the first PMI and the first RI,respectively, is determined either based on one another or either CQI orthe CQI and the second RI.

In some embodiments, the RF transceivers 210 a-210 n are capable ofreceiving at least one of the first or second CSI report using at leastone of a physical uplink shared channel (PUSCH) Mode 0-1 or a PUSCH Mode3-1 based on aperiodic CSI feedback configuration information; orreceiving both of the first and second CSI reports using a PUCCH Mode3-2 based on the aperiodic CSI feedback configuration information. Insuch embodiments, the aperiodic CSI feedback configuration informationfor an aperiodic CSI reporting is received from the eNB.

The TX processing circuitry 215 receives analog or digital data (such asvoice data, web data, e-mail, or interactive video game data) from thecontroller/processor 225. The TX processing circuitry 215 encodes,multiplexes, and/or digitizes the outgoing baseband data to generateprocessed baseband or IF signals. The RF transceivers 210 a-210 nreceive the outgoing processed baseband or IF signals from the TXprocessing circuitry 215 and up-converts the baseband or IF signals toRF signals that are transmitted via the antennas 205 a-205 n.

The controller/processor 225 can include one or more processors or otherprocessing devices that control the overall operation of the eNB 102.For example, the controller/processor 225 could control the reception offorward channel signals and the transmission of reverse channel signalsby the RF transceivers 210 a-210 n, the RX processing circuitry 220, andthe TX processing circuitry 215 in accordance with well-knownprinciples. The controller/processor 225 could support additionalfunctions as well, such as more advanced wireless communicationfunctions. For instance, the controller/processor 225 could support beamforming or directional routing operations in which outgoing signals frommultiple antennas 205 a-205 n are weighted differently to effectivelysteer the outgoing signals in a desired direction. Any of a wide varietyof other functions could be supported in the eNB 102 by thecontroller/processor 225. In some embodiments, the controller/processor225 includes at least one microprocessor or microcontroller. Asdescribed in more detail below, the eNB 102 may include circuitry,programming, or a combination thereof for processing of CSI reporting onPUCCH. For example, controller/processor 225 can be configured toexecute one or more instructions, stored in memory 230, that areconfigured to cause the controller/processor to process vector quantizedfeedback components such as channel coefficients.

The controller/processor 225 is also capable of executing programs andother processes resident in the memory 230, such as an OS. Thecontroller/processor 225 can move data into or out of the memory 230 asrequired by an executing process.

The controller/processor 225 is also coupled to the backhaul or networkinterface 235. The backhaul or network interface 235 allows the eNB 102to communicate with other devices or systems over a backhaul connectionor over a network. The interface 235 could support communications overany suitable wired or wireless connection(s). For example, when the eNB102 is implemented as part of a cellular communication system (such asone supporting 5G, LTE, or LTE-A), the interface 235 could allow the eNB102 to communicate with other eNBs over a wired or wireless backhaulconnection. When the eNB 102 is implemented as an access point, theinterface 235 could allow the eNB 102 to communicate over a wired orwireless local area network or over a wired or wireless connection to alarger network (such as the Internet). The interface 235 includes anysuitable structure supporting communications over a wired or wirelessconnection, such as an Ethernet or RF transceiver.

In some embodiments, the controller/processor 225 is capable ofdetermining a first CSI reference signal (CSI-RS) and a second CSI-RSconfigured for a periodic CSI reporting based on at least two differentenhanced MIMO types (eMIMO-Types), the at least two differenteMIMO-Types comprising a first eMIMO-Type and a second eMIMO-Type thatare generated using at least two different antenna port configurations,respectively; and determining a periodic reporting interval for each ofa first CSI report and a second CSI report, wherein the periodicreporting interval for the first CSI report is determined based on atleast one of a periodicity value or an offset value corresponding to thefirst CSI report, and at least one periodicity value and at least oneoffset value corresponding to the second CSI report.

In some embodiments, the controller/processor 225 is capable ofdetermining the first CSI-RS that is a non-precoded (NP) CSI-RS and thesecond CSI-RS that is a beamformed (BF) CSI-RS with K=1 resource.

The memory 230 is coupled to the controller/processor 225. Part of thememory 230 could include a RAM, and another part of the memory 230 couldinclude a Flash memory or other ROM.

Although FIG. 2 illustrates one example of eNB 102, various changes maybe made to FIG. 2. For example, the eNB 102 could include any number ofeach component shown in FIG. 2. As a particular example, an access pointcould include a number of interfaces 235, and the controller/processor225 could support routing functions to route data between differentnetwork addresses. As another particular example, while shown asincluding a single instance of TX processing circuitry 215 and a singleinstance of RX processing circuitry 220, the eNB 102 could includemultiple instances of each (such as one per RF transceiver). Also,various components in FIG. 2 could be combined, further subdivided, oromitted and additional components could be added according to particularneeds.

FIG. 3 illustrates an example UE 116 according to embodiments of thepresent disclosure. The embodiment of the UE 116 illustrated in FIG. 3is for illustration only, and the UEs 111-115 of FIG. 1 could have thesame or similar configuration. However, UEs come in a wide variety ofconfigurations, and FIG. 3 does not limit the scope of this disclosureto any particular implementation of a UE.

As shown in FIG. 3, the UE 116 includes an antenna 305, a radiofrequency (RF) transceiver 310, TX processing circuitry 315, amicrophone 320, and receive (RX) processing circuitry 325. The UE 116also includes a speaker 330, a processor 340, an input/output (I/O)interface (IF) 345, a touchscreen 350, a display 355, and a memory 360.The memory 360 includes an operating system (OS) 361 and one or moreapplications 362.

The RF transceiver 310 receives, from the antenna 305, an incoming RFsignal transmitted by an eNB of the network 100. The RF transceiver 310down-converts the incoming RF signal to generate an intermediatefrequency (IF) or baseband signal. The IF or baseband signal is sent tothe RX processing circuitry 325, which generates a processed basebandsignal by filtering, decoding, and/or digitizing the baseband or IFsignal. The RX processing circuitry 325 transmits the processed basebandsignal to the speaker 330 (such as for voice data) or to the processor340 for further processing (such as for web browsing data).

In some embodiments, the RF transceiver 310 is capable of receiving,from an eNodeB (eNB), periodic CSI feedback configuration informationincluding a periodicity value and an offset value corresponding to afirst CSI report, and at least one periodicity value and at least oneoffset value corresponding to a second CSI report.

In some embodiments, the RF transceiver 310 is capable of jointlyreporting at least one of a first PMI or a first RI that is included inthe first CSI report; and reporting each of the first and second CSIreports based on the determined periodic reporting interval using thePUCCH format, wherein the determined periodic reporting interval of thefirst CSI report is determined based on at least one of the periodicityvalue M_(PMI/RI) or the offset value N_(OFFSET,PMI/RI) included in theperiodic CSI feedback configuration information, wherein the periodicityvalue M_(PMI/RI) is determined based on at least one of the periodicityvalues M_(RI) and N_(pd) for the second RI, or CQI, respectively, andwherein the offset value N_(OFFSET,PMI/RI) is determined based on atleast one of the offset values N_(OFFSET,CQI) and N_(OFFSET,RI) for theCQI or the second RI, respectively.

In some embodiments, the RF transceiver 310 is capable of jointlyreporting wideband first PMI and first RI included in the first CSIreport in subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,PMI/RI))mod(n_(pd)·M_(RI)·M_(PMI/RI))=0if a number of antenna ports associated with the second eMIMO-Type ismore than 1 and(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,PMI/RI))mod(N_(pd)·M_(PMI/RI))=0if the number of antenna ports associated with the second eMIMO-Type is1.

In some embodiments, the RF transceiver 310 is capable of separatelyreporting first PMI and first RI that are included in the first CSIreport; and reporting each of the first and second CSI reports based onthe determined periodic reporting interval using the PUCCH format,wherein each of the periodic reporting intervals for first PMI and afirst RI, respectively, is determined based on the at least one of theperiodicity value or the offset value included in the periodic CSIfeedback configuration information, wherein each of the periodicityvalues for the first PMI and the first RI, respectively, is determinedeither based on one another or at least one of the second RI or CQI, andwherein each of the offset values for the first PMI and the first RI,respectively, is determined either based on one another or either CQI orthe CQI and the second RI.

In some embodiments, the RF transceiver 310 is capable of reporting atleast one of the first or second CSI report using at least one of aphysical uplink shared channel (PUSCH) Mode 0-1 or a PUSCH Mode 3-1based on aperiodic CSI feedback configuration information; or reportingboth of the first and second CSI reports using a PUCCH Mode 3-2 based onthe aperiodic CSI feedback configuration information. In suchembodiments, the aperiodic CSI feedback configuration information for anaperiodic CSI reporting is received from the eNB.

The TX processing circuitry 315 receives analog or digital voice datafrom the microphone 320 or other outgoing baseband data (such as webdata, e-mail, or interactive video game data) from the processor 340.The TX processing circuitry 315 encodes, multiplexes, and/or digitizesthe outgoing baseband data to generate a processed baseband or IFsignal. The RF transceiver 310 receives the outgoing processed basebandor IF signal from the TX processing circuitry 315 and up-converts thebaseband or IF signal to an RF signal that is transmitted via theantenna 305.

The processor 340 can include one or more processors or other processingdevices and execute the OS 361 stored in the memory 360 in order tocontrol the overall operation of the UE 116. For example, the processor340 could control the reception of forward channel signals and thetransmission of reverse channel signals by the RF transceiver 310, theRX processing circuitry 325, and the TX processing circuitry 315 inaccordance with well-known principles. In some embodiments, theprocessor 340 includes at least one microprocessor or microcontroller.

The processor 340 is also capable of executing other processes andprograms resident in the memory 360, such as processes for CSI reportingon PUCCH. The processor 340 can move data into or out of the memory 360as required by an executing process. In some embodiments, the processor340 is configured to execute the applications 362 based on the OS 361 orin response to signals received from eNBs or an operator. The processor340 is also coupled to the I/O interface 345, which provides the UE 116with the ability to connect to other devices, such as laptop computersand handheld computers. The I/O interface 345 is the communication pathbetween these accessories and the processor 340.

In some embodiments, the processor 340 is also capable of measuring afirst CSI reference signal (CSI-RS) and a second CSI-RS configured for aperiodic CSI reporting based on at least two different enhanced MIMOtypes (eMIMO-Types), the at least two different eMIMO-Types comprising afirst eMIMO-Type and a second eMIMO-Type that are generated using atleast two different antenna port configurations, respectively;generating the first CSI report and the second CSI report for the firsteMIMO-Type and the second eMIMO-Type, respectively, the first CSI reportand the second CSI report being associated with the first CSI-RS and thesecond CSI-RS, respectively; determining a periodic reporting intervalfor each of the first CSI report and the second CSI report, wherein theperiodic reporting interval for the first CSI report is determined basedon at least one of the periodicity value or the offset valuecorresponding to the first CSI report, and at least one periodicityvalue and at least one offset value corresponding to the second CSIreport; and reporting the first and second CSI reports based on thedetermined periodic reporting intervals using a physical uplink controlchannel (PUCCH) format 2 or a PUCCH format 3 or a combination of thePUCCH format 2 and the PUCCH format 3.

In some embodiments, the processor 340 is also capable of measuring thefirst CSI-RS that is a non-precoded (NP) CSI-RS and the second CSI-RSthat is a beamformed (BF) CSI-RS with K=1 resource; generating at leastone of a first precoding matrix index (PMI) or a first rank indicator(RI) that is included in the first CSI report associated with the firsteMIMO-Type, wherein the first PMI comprises at least one of a single PMIor a pair of two PMIs and the first eMIMO-Type is Class A; andgenerating at least one of a second PMI, a second RI, or a channelquality indicator (CQI) that is included in the second CSI reportassociated with the second eMIMO-Type, wherein and the second eMIMO-Typeis Class B with K=1 resource.

In some embodiments, the processor 340 is also capable of measuring thefirst CSI-RS for the first CSI report based on the first eMIMO-Typegenerated using a subset of antenna ports, and wherein the first CSI-RScomprises an NP CSI-RS.

The processor 340 is also coupled to the touchscreen 350 and the display355. The operator of the UE 116 can use the touchscreen 350 to enterdata into the UE 116. The display 355 may be a liquid crystal display,light emitting diode display, or other display capable of rendering textand/or at least limited graphics, such as from web sites.

The memory 360 is coupled to the processor 340. Part of the memory 360could include a random access memory (RAM), and another part of thememory 360 could include a Flash memory or other read-only memory (ROM).

Although FIG. 3 illustrates one example of UE 116, various changes maybe made to FIG. 3. For example, various components in FIG. 3 could becombined, further subdivided, or omitted and additional components couldbe added according to particular needs. As a particular example, theprocessor 340 could be divided into multiple processors, such as one ormore central processing units (CPUs) and one or more graphics processingunits (GPUs). Also, while FIG. 3 illustrates the UE 116 configured as amobile telephone or smartphone, UEs could be configured to operate asother types of mobile or stationary devices.

FIG. 4A is a high-level diagram of transmit path circuitry 400. Forexample, the transmit path circuitry 400 may be used for an orthogonalfrequency division multiple access (OFDMA) communication. FIG. 4B is ahigh-level diagram of receive path circuitry 450. For example, thereceive path circuitry 450 may be used for an orthogonal frequencydivision multiple access (OFDMA) communication. In FIGS. 4A and 4B, fordownlink communication, the transmit path circuitry 400 may beimplemented in a base station (eNB) 102 or a relay station, and thereceive path circuitry 450 may be implemented in a user equipment (e.g.user equipment 116 of FIG. 1). In other examples, for uplinkcommunication, the receive path circuitry 450 may be implemented in abase station (e.g. eNB 102 of FIG. 1) or a relay station, and thetransmit path circuitry 400 may be implemented in a user equipment (e.g.user equipment 116 of FIG. 1).

Transmit path circuitry 400 comprises channel coding and modulationblock 405, serial-to-parallel (S-to-P) block 410, Size N Inverse FastFourier Transform (IFFT) block 415, parallel-to-serial (P-to-S) block420, add cyclic prefix block 425, and up-converter (UC) 430. Receivepath circuitry 450 comprises down-converter (DC) 455, remove cyclicprefix block 460, serial-to-parallel (S-to-P) block 465, Size N FastFourier Transform (FFT) block 470, parallel-to-serial (P-to-S) block475, and channel decoding and demodulation block 480.

At least some of the components in FIGS. 4A and 4B may be implemented insoftware, while other components may be implemented by configurablehardware or a mixture of software and configurable hardware. Inparticular, it is noted that the FFT blocks and the IFFT blocksdescribed in this disclosure document may be implemented as configurablesoftware algorithms, where the value of Size N may be modified accordingto the implementation.

Furthermore, although this disclosure is directed to an embodiment thatimplements the Fast Fourier Transform and the Inverse Fast FourierTransform, this is by way of illustration only and should not beconstrued to limit the scope of the disclosure. It will be appreciatedthat in an alternate embodiment of the disclosure, the Fast FourierTransform functions and the Inverse Fast Fourier Transform functions mayeasily be replaced by discrete Fourier transform (DFT) functions andinverse discrete Fourier transform (IDFT) functions, respectively. Itwill be appreciated that for DFT and IDFT functions, the value of the Nvariable may be any integer number (i.e., 1, 4, 3, 4, etc.), while forFFT and IFFT functions, the value of the N variable may be any integernumber that is a power of two (i.e., 1, 2, 4, 8, 16, etc.).

In transmit path circuitry 400, channel coding and modulation block 405receives a set of information bits, applies coding (e.g., LDPC coding)and modulates (e.g., quadrature phase shift keying (QPSK) or quadratureamplitude modulation (QAM)) the input bits to produce a sequence offrequency-domain modulation symbols. Serial-to-parallel block 410converts (i.e., de-multiplexes) the serial modulated symbols to paralleldata to produce N parallel symbol streams where N is the IFFT/FFT sizeused in BS 102 and UE 116. Size N IFFT block 415 then performs an IFFToperation on the N parallel symbol streams to produce time-domain outputsignals. Parallel-to-serial block 420 converts (i.e., multiplexes) theparallel time-domain output symbols from Size N IFFT block 415 toproduce a serial time-domain signal. Add cyclic prefix block 425 theninserts a cyclic prefix to the time-domain signal. Finally, up-converter430 modulates (i.e., up-converts) the output of add cyclic prefix block425 to RF frequency for transmission via a wireless channel. The signalmay also be filtered at baseband before conversion to RF frequency.

The transmitted RF signal arrives at UE 116 after passing through thewireless channel, and reverse operations to those at eNB 102 areperformed. Down-converter 455 down-converts the received signal tobaseband frequency, and remove cyclic prefix block 460 removes thecyclic prefix to produce the serial time-domain baseband signal.Serial-to-parallel block 465 converts the time-domain baseband signal toparallel time-domain signals. Size N FFT block 470 then performs an FFTalgorithm to produce N parallel frequency-domain signals.Parallel-to-serial block 475 converts the parallel frequency-domainsignals to a sequence of modulated data symbols. Channel decoding anddemodulation block 480 demodulates and then decodes the modulatedsymbols to recover the original input data stream.

Each of eNBs 101-103 may implement a transmit path that is analogous totransmitting in the downlink to user equipment 111-116 and may implementa receive path that is analogous to receiving in the uplink from userequipment 111-116. Similarly, each one of user equipment 111-116 mayimplement a transmit path corresponding to the architecture fortransmitting in the uplink to eNBs 101-103 and may implement a receivepath corresponding to the architecture for receiving in the downlinkfrom eNBs 101-103.

Various embodiments of the present disclosure provides for ahigh-performance, scalability with respect to the number and geometry oftransmit antennas, and a flexible CSI feedback (e.g., reporting)framework and structure for LTE enhancements when FD-MIMO with largetwo-dimensional antenna arrays is supported. To achieve highperformance, more accurate CSI in terms MIMO channel is needed at theeNB especially for FDD scenarios. In this case, embodiments of thepresent disclosure recognize that the previous LTE (e.g. Rel. 12)precoding framework (PMI-based feedback) may need to be replaced. Inthis disclosure, properties of FD-MIMO are factored in for the presentdisclosure. For example, the use of closely spaced large 2D antennaarrays that is primarily geared toward high beamforming gain rather thanspatial multiplexing along with relatively small angular spread for eachUE. Therefore, compression or dimensionality reduction of the channelfeedback in accordance with a fixed set of basis functions and vectorsmay be achieved. In another example, updated channel feedback parameters(e.g., the channel angular spreads) may be obtained at low mobilityusing UE-specific higher-layer signaling. In addition, a CSI reporting(feedback) may also be performed cumulatively.

Another embodiment of the present disclosure incorporates a CSIreporting method and procedure with a reduced PMI feedback. This PMIreporting at a lower rate pertains to long-term DL channel statisticsand represents a choice of a group of precoding vectors recommended by aUE to an eNB. The present disclosure also includes a DL transmissionmethod wherein an eNB transmits data to a UE over a plurality ofbeamforming vectors while utilizing an open-loop diversity scheme.Accordingly, the use of long-term precoding ensures that open-looptransmit diversity is applied only across a limited number of ports(rather than all the ports available for FD-MIMO, e.g., 64). This avoidshaving to support excessively high dimension for open-loop transmitdiversity that reduces CSI feedback overhead and improves robustnesswhen CSI measurement quality is questionable.

FIG. 5 illustrates an example structure for a DL subframe 500 accordingto embodiments of the present disclosure. An embodiment of the DLsubframe structure 500 shown in FIG. 1 is for illustration only. Otherembodiments may be used without departing from the scope of the presentdisclosure. The downlink subframe (DL SF) 510 includes two slots 520 anda total of N_(symb) ^(DL) symbols for transmitting of data informationand downlink control information (DCI). The first M_(symb) ^(DL) SFsymbols are used to transmit PDCCHs and other control channels 530 (notshown in FIG. 5). The remaining Z SF symbols are primarily used totransmit physical downlink shared channels (PDSCHs) 540, 542, 544, 546,and 548 or enhanced physical downlink control channels (EPDCCHs) 550,552, 554, and 556. A transmission bandwidth (BW) comprises frequencyresource units referred to as resource blocks (RBs). Each RB compriseseither N_(sc) ^(RB) sub-carriers or resource elements (REs) (such as 12Res). A unit of one RB over one subframe is referred to as a physical RB(PRB). A UE is allocated to M_(PDSCH) RBs for a total ofZ=O_(F)+└(n_(s0)+Y·N_(EPDCCH)/D┘ REs for a PDSCH transmission BW. AnEPDCCH transmission is achieved in either one RB or multiple of RBs.

FIG. 6 illustrates an example transmission structure of a physicaluplink shared channel (PUSCH) subframe or a physical uplink controlchannel (PUCCH) subframe 600. Embodiments of the transmission structurefor the PUSCH or the PUCCH over the UL subframe shown in FIG. 6 is forillustration only. Other embodiments could be used without departingfrom the scope of the present disclosure. A UL subframe 610 includes twoslots. Each slot 620 includes N_(symb) ^(UL) symbols 630 fortransmitting data information, uplink control information (UCI),demodulation reference signals (DMRS), or sounding RSs (SRSs). Afrequency resource unit of an UL system BW is a RB. A UE is allocated toN_(RB) RBs 640 for a total of N_(RB)·N_(sc) ^(RB) resource elements(Res) for a transmission BW. For a PUCCH, N=1. A last subframe symbol isused to multiplex SRS transmissions 650 from one or more UEs. A numberof subframe symbols that are available for data/UCI/DMRS transmission isN_(symb)=2·(N_(symb) ^(UL)−1)−N_(SRS), where N_(SRS)=1 if a lastsubframe symbol is used to transmit SRS and N_(SRS)=0 otherwise.

FIG. 7 illustrates an example transmitter block diagram for a physicaldownlink shared channel (PDSCH) subframe 700 according to embodiments ofthe present disclosure. An embodiment of the PDSCH transmitter blockdiagram 700 shown in FIG. 7 is for illustration only. Other embodimentsare used without departing from the scope of the present disclosure.

Information bits 710 are encoded by an encoder 720 (such as a turboencoder) and modulated by a modulator 730, for example using aquadrature phase shift keying (QPSK) modulation. A Serial to Parallel(S/P) converter 740 generates M modulation symbols that are subsequentlyprovided to a mapper 750 to be mapped to REs selected by a transmissionBW selection unit 755 for an assigned PDSCH transmission BW, unit 760applies an inverse fast fourier transform (IFFT). An output is thenserialized by a parallel to a serial (P/S) converter 770 to create atime domain signal, filtering is applied by a filter 780, and thensignal is transmitted. Additional functionalities, such as datascrambling, a cyclic prefix insertion, a time windowing, aninterleaving, and others are well known in the art and are not shown forbrevity.

FIG. 8 illustrates an example receiver block diagram for a packet datashared channel (PDSCH) subframe 800 according to embodiments of thepresent disclosure. An embodiment of the PDSCH receiver block diagram800 shown in FIG. 8 is for illustration only. One or more of thecomponents illustrated in FIG. 8 can be implemented in specializedcircuitry configured to perform the noted functions or one or more ofthe components can be implemented by one or more processors executinginstructions to perform the noted functions. Other embodiments can beused without departing from the scope of the present disclosure.

A received signal 810 is filtered by a filter 820, and then is output toa resource element (RE) demapping block 830. The RE demapping 830assigns a reception bandwidth (BW) that is selected by a BW selector835. The BW selector 835 is configured to control a transmission BW. Afast Fourier transform (FFT) circuit 840 applies a FFT. The output ofthe FFT circuitry 840 is serialized by a parallel-to-serial converter850. Subsequently, a demodulator 860 coherently demodulates data symbolsby applying a channel estimate obtained from a demodulation referencesignal (DMRS) or a common reference signal (CRS) (not shown), and then adecoder 870 decodes demodulated data to provide an estimate of theinformation data bits 880. The decoder 870 can be configured toimplement any decoding process, such as a turbo decoding process.Additional functionalities such as time-windowing, a cyclic prefixremoval, a de-scrambling, channel estimation, and a de-interleaving arenot shown for brevity.

FIG. 9 illustrates a transmitter block diagram for a physical uplinkshared channel (PUSCH) subframe 900 according to embodiments of thepresent disclosure. One or more of the components illustrated in FIG. 9can be implemented in specialized circuitry configured to perform thenoted functions or one or more of the components can be implemented byone or more processors executing instructions to perform the notedfunctions. An embodiment of the PUSCH transmitter block diagram 900shown in FIG. 9 is for illustration only. Other embodiments are usedwithout departing from the scope of the present disclosure.

Information data bits 910 are encoded by an encoder 920 and modulated bya modulator 930. Encoder 920 can be configured to implement any encodingprocess, such as a turbo coding process. A discrete Fourier transform(DFT) circuitry 940 applies a DFT on the modulated data bits. REs aremapped by an RE mapping circuit 950. The REs corresponding to anassigned PUSCH transmission BW are selected by a transmission BWselection unit 955. An inverse FFT (IFFT) circuit 960 applies an IFFT tothe output of the RE mapping circuit 950. After a cyclic prefixinsertion (not shown), filter 970 applies a filtering. The filteredsignal then is transmitted.

FIG. 10 illustrates an example receiver block diagram for a PUSCHsubframe 1000 according to embodiments of the present disclosure. Anembodiment of the PUSCH receiver block diagram 1000 shown in FIG. 10 isfor illustration only. One or more of the components illustrated in FIG.10 can be implemented in specialized circuitry configured to perform thenoted functions or one or more of the components can be implemented byone or more processors executing instructions to perform the notedfunctions. Other embodiments are used without departing from the scopeof the present disclosure.

A received signal 1010 is filtered by a filter 1020. Subsequently, aftera cyclic prefix is removed (not shown), an FFT circuit 1030 applies anFFT. REs are mapped by an RE mapping circuit 1040. REs 1040corresponding to an assigned PUSCH reception BW are selected by areception BW selector 1045. An inverse DFT (IDFT) circuit 1050 appliesan IDFT. Demodulator 1060 receives an output from IDFT circuit 1050 andcoherently demodulates data symbols by applying a channel estimateobtained from a DMRS (not shown). A decoder 1070 decodes the demodulateddata to provide an estimate of the information data bits 1080. Thedecoder 1070 can be configured to implement any decoding process, suchas a turbo decoding process.

FIG. 11 illustrates an example configuration of a two dimensional (2D)antenna array 1100 which is constructed from 16 dual-polarized antennaelements arranged in a 4×4 rectangular format according to embodimentsof the present disclosure. In this illustration, each labelled antennaelement is logically mapped onto a single antenna port. Two alternativelabelling conventions are depicted for illustrative purposes (such as ahorizontal first in 1110 and a vertical first in 1120). In oneembodiment, one antenna port corresponds to multiple antenna elements(such as physical antennas) combined via a virtualization. This 4×4 dualpolarized array is then viewed as 16×2=32-element array of elements. Thevertical dimension (such as including 4 rows) facilitates an elevationbeamforming in addition to an azimuthal beamforming across a horizontaldimension including 4 columns of dual polarized antennas. A MIMOprecoding in Rel. 12 of the LTE standardization was largely designed tooffer a precoding gain for one-dimensional antenna array. While fixedbeamforming (such as antenna virtualization) is implemented across anelevation dimension, it is unable to reap a potential gain offered by aspatial and frequency selective nature of channels.

In 3GPP LTE specification, MIMO precoding (for beamforming or spatialmultiplexing) can be facilitated via precoding matrix index (PMI)reporting as a component of channel state information (CSI) reporting.The PMI report is derived from one of the following sets of standardizedcodebooks: two antenna ports (single-stage); four antenna ports(single-stage or dual-stage); eight antenna ports (dual-stage);configurable dual-stage eMIMO-Type of ‘CLASS A’ codebook for eight,twelve, or sixteen antenna ports (also known as ‘nonPrecoded);’ andsingle-stage eMIMO-Type of ‘CLASS B’ codebook for two, four, or eightantenna ports (also known as ‘beamformed’).

If an eNodeB follows a PMI recommendation from a UE, the eNB is expectedto precode the eNB's transmitted signal according to a recommendedprecoding vector or matrix for a given subframe and RB. Regardlesswhether the eNB follows this recommendation, the UE is configured toreport a PMI according to a configured precoding codebook. Here a PMI,which may consist of a single index or a pair of indices, is associatedwith a precoding matrix W in an associated codebook.

When dual-stage class A codebook is configured, a resulting precodingmatrix can be described in equation (1). That is, the first stageprecoder can be described as a Kronecker product of a first and a secondprecoding vector (or matrix), which can be associated with a first and asecond dimension, respectively. This type is termed partial KroneckerProduct (partial KP) codebook. The subscripts m and n inW_(m,n)(i_(m,n)) denote precoding stage (first or second stage) anddimension (first or second dimension), respectively. Each of theprecoding matrices W_(m,n) can be described as a function of an indexwhich serves as a PMI component. As a result, the precoding matrix W canbe described as a function of 3 PMI components. The first stage pertainsto a long-term component. Therefore it is associated with long-termchannel statistics such as the aforementioned AoD profile and AoDspread. On the other hand, the second stage pertains to a short-termcomponent which performs selection, co-phasing, or any linear operationto the first component precoder W_(1,1)(i_(1,1))

W_(1,2)(i_(1,2)). The preceder W₂(i₂), therefore, performs a lineartransformation of the long-term component such as a linear combinationof a set of basis functions or vectors associated with the columnvectors of W_(1,1) (i_(1,1))

W_(1,2)(i_(1,2))).

$\begin{matrix}{{W( {i_{1,1},i_{1,2},i_{2}} )} = {\underset{W_{1}{({i_{1,1},i_{1,2}})}}{( \underset{}{ {{W_{1,1}( i_{1,1} )} \otimes {W_{1,2}( i_{1,2} )}} )} }{W_{2}( i_{2} )}}} & (1)\end{matrix}$

The above discussion assumes that the serving eNB transmits and a servedUE measures non-precoded CSI-RS (NP CSI-RS). That is, a cell-specificone-to-one mapping between CSI-RS port and TXRU is utilized. Here,different CSI-RS ports have the same wide beam width and direction andhence generally cell wide coverage. This use case can be realized whenthe eNB configures the UE with ‘CLASS A’ eMIMO-Type which corresponds toNP CSI-RS. Other than CQI and RI, CSI reports associated with ‘CLASS A’or ‘nonPrecoded’ eMIMO-Type include a three-component PMI {i_(1,1),i_(1,2), i₂}.

Another type of CSI-RS applicable to FD-MIMO is beamformed CSI-RS (BFCSI-RS). In this case, beamforming operation, either cell-specific (withK>1 CSI-RS resources) or UE-specific (with K=1 CSI-RS resource), isapplied on a non-zero-power (NZP) CSI-RS resource (consisting ofmultiple ports). Here, (at least at a given time/frequency) CSI-RS portshave narrow beam widths and hence not cell wide coverage, and (at leastfrom the eNB perspective) at least some CSI-RS port-resourcecombinations have different beam directions. This beamforming operationis intended to increase CSI-RS coverage.

In addition, when UE-specific beamforming is applied to CSI-RS resource(termed the UE-specific or UE-specifically beamformed CSI-RS), CSI-RSoverhead reduction is possible. UE complexity reduction is also evidentsince the configured number of ports tends to be much smaller than itsNP CSI-RS counterpart. When a UE is configured to receive BF CSI-RS froma serving eNB, the UE can be configured to report PMI parameter(s)associated with a second-stage precoder without the associatedfirst-stage precoder or, in general, associated with a single-stageprecoder/codebook. This use case can be realized when the eNB configuresthe UE with ‘CLASS B’ eMIMO-Type which corresponds to BF CSI-RS. Otherthan CQI and RI, CSI reports associated with ‘CLASS B’ or ‘beamformed’eMIMO-Type (with one CSI-RS resource and alternative codebook) include aone-component PMI n. Although a single PMI defined with respect to adistinct codebook, this PMI can be associated with the second-stage PMIcomponent of ‘CLASS A’/‘nonPrecoded’ codebooks i₂.

Therefore, given a precoding codebook (a set of precoding matrices), aUE measures a CSI-RS in a subframe designated to carry CSI-RS,calculates/determines a CSI (including PMI, RI, and CQI where each ofthese three CSI parameters can consist of multiple components) based onthe measurement, and reports the calculated CSI to a serving eNB. Inparticular, this PMI is an index of a recommended precoding matrix inthe precoding codebook. Similar to that for the first type, differentprecoding codebooks can be used for different values of RI. The measuredCSI-RS can be one of the two types: non-precoded (NP) CSI-RS andbeamformed (BF) CSI-RS. As mentioned, in Rel. 13, the support of thesetwo types of CSI-RS is given in terms of two eMIMO-Types: ‘CLASS A’(with one CSI-RS resource) and ‘CLASS B’ (with one or a plurality ofCSI-RS resources), respectively.

In scenarios where DL long-term channel statistics can be measuredthrough UL signals at a serving eNB, UE-specific BF CSI-RS can bereadily used. This is typically feasible when UL-DL duplex distance issufficiently small. When this condition does not hold, however, some UEfeedback is necessary for the eNB to obtain an estimate of DL long-termchannel statistics (or any of its representation thereof). To facilitatesuch a procedure, a first BF CSI-RS transmitted with periodicity T1 (ms)and a second NP CSI-RS transmitted with periodicity T2 (ms), whereT1≦T2. This approach is termed hybrid CSI-RS. The implementation ofhybrid CSI-RS is largely dependent on the definition of CSI process andNZP CSI-RS resource.

In LTE specification, the aforementioned precoding codebooks areutilized for CSI reporting. Two schemes of CSI reporting modes aresupported (e.g., PUSCH-based aperiodic CSI (A-CSI) and PUCCH-basedperiodic CSI (P-CSI)). In each scheme, different modes are defined basedon frequency selectivity of CQI and/or PMI, that is, whether wideband orsubband reporting is performed. The supported CSI reporting modes aregiven in Table 1.

TABLE 1 CQI and PMI Feedback Types for PUSCH CSI reporting Modes PMIFeedback Type Single Multiple No PMI PMI PMI PUSCH CQI Wideband Mode 1-2Feedback (wideband CQI) Type UE Selected Mode 2-0 Mode 2-2 (subband CQI)Higher Layer- Mode 3-0 Mode 3-1 Mode 3-2 configured (subband CQI)

TABLE 2 CQI and PMI Feedback Types for PUCCH CSI reporting Modes PMIFeedback Type Single No PMI PMI PUCCH CQI Wideband Mode 1-0 Mode 1-1Feedback (wideband Type CQI) UE Selected Mode 2-0 Mode 2-1 (subband CQI)

According to the WI, the hybrid CSI reporting based on non-precoded andbeam-formed CSI-RS associated with two eMIMO-Types may be supported inLTE specification.

In the present disclosure, for brevity, FDD is considered as the duplexmethod for both DL and UL signaling but the embodiments of the presentdisclosure are also directly applicable to TDD.

Terms such as ‘non-precoded’ (or ‘NP’) CSI-RS and ‘beamformed’ (or ‘BF’)CSI-RS are used throughout this present disclosure. The presentdisclosure does not change when different terms or names are used torefer to these two CSI-RS types. The same holds for CSI-RS resource.CSI-RS resources associated with these two types of CSI-RS can bereferred to as ‘a first CSI-RS resource’ and ‘a second CSI-RS resource’,or ‘CSI-RS-A resource’ and ‘CSI-RS-B resource’. Subsequently, the labels‘NP’ and ‘BF’ (or ‘np’ and ‘bf’) are exemplary and can be substitutedwith other labels such as ‘1’ and ‘2’, ‘A’ or ‘B’. Alternatively,instead of using categories such as CSI-RS type or CSI-RS resource type,a category of CSI reporting class can also be used. For instance, NPCSI-RS is associated with eMIMO-Type of ‘CLASS A’ while UE-specific BFCSI-RS is associated with eMIMO-Type of ‘CLASS B’ with one CSI-RSresource.

Throughout the present disclosure, 2D dual-polarized array is usedsolely for illustrative purposes, unless stated otherwise. Extensions to2D single-polarized array are straightforward for those skilled in theart.

FIG. 12 illustrates an example dual-polarized antenna port layouts for{2, 4, 8, 12, 16} ports 1200 according to embodiments of the presentdisclosure. An embodiment of the dual-polarized antenna port layouts for{2, 4, 8, 12, 16} ports 1200 shown in FIG. 12 is for illustration only.One or more of the components illustrated in FIG. 12 can be implementedin specialized circuitry configured to perform the noted functions orone or more of the components can be implemented by one or moreprocessors executing instructions to perform the noted functions. Otherembodiments are used without departing from the scope of the presentdisclosure.

As shown in FIG. 12, 2D antenna arrays are constructed from N₁×N₂dual-polarized antenna elements arranged in a (N₁, N₂) rectangularformat for 2, 4, 8, 12, 16 antenna ports. In FIG. 12, each antennaelement is logically mapped onto a single antenna port. In general, oneantenna port may correspond to multiple antenna elements (physicalantennas) combined via a virtualization. This N₁×N₂ dual polarized arraycan then be viewed as 2N₁N₂-element array of elements.

The first dimension consists of N₁ columns and facilitates azimuthbeamforming. The second dimension similarly consists of N₂ rows andallows elevation beamforming. MIMO precoding in LTE specification waslargely designed to offer precoding (beamforming) gain forone-dimensional (1D) antenna array using 2, 4, 8 antenna ports, whichcorrespond to (N₁, N₂) belonging to {(1, 1), (2, 1), (4, 1)}. Whilefixed beamforming (i.e. antenna virtualization) can be implementedacross the elevation dimension, it is unable to reap the potential gainoffered by the spatial and frequency selective nature of the channel.Therefore, MIMO precoding in LTE specification is designed to offerprecoding gain for two-dimensional (2D) antenna array using 8, 12, 16antenna ports, which correspond to (N₁, N₂) belonging to {(2, 2), (2,3), (3, 2), (8, 1), (4, 2), (2, 4)}.

Although (N₁, N₂)=(6, 1) case has not been supported in LTEspecification, it may be supported in future releases. The embodimentsof the present disclosure are general and are applicable to any (N₁, N₂)values including (N₁, N₂)=(6, 1). The first and second dimensions asshown in FIG. 12 are for illustration only. The present disclosure isapplicable to the case, in which they are swapped, i.e., first andsecond dimensions respectively correspond to elevation and azimuth orany other pair of directions.

FIG. 13 illustrates an example dual-polarized antenna port layouts for{20, 24, 28, 32} ports 1300 according to embodiments of the presentdisclosure. An embodiment of the dual-polarized antenna port layouts for{20, 24, 28, 32} ports 1300 shown in FIG. 13 is for illustration only.One or more of the components illustrated in FIG. 13 can be implementedin specialized circuitry configured to perform the noted functions orone or more of the components can be implemented by one or moreprocessors executing instructions to perform the noted functions. Otherembodiments are used without departing from the scope of the presentdisclosure.

According to LTE specification, an eFD-MIMO may support {20, 24, 28, 32}antenna ports. Assuming rectangular (1D or 2D) port layouts, there areseveral possible (N₁, N₂) values for {20, 24, 28, 32} ports. Anillustration of 1D and 2D antenna port layouts for these (N₁, N₂) valuesare shown in FIG. 13.

In some embodiments, a UE is configured with one or both of the twotypes of CSI-RS resources. In one example, the “first non-zero-power(NZP) CSI-RS resource” corresponds to either a full port (e.g. CSI-RS istransmitted from all 2N₁N₂ ports and it is non-precoded (NP) or Class AeMIMO-Type) or a partial port (e.g. CSI-RS is transmitted from a subsetof 2N₁N₂ ports). In such example, NP CSI-RS or Class A eMIMO-Type, orbeam-formed (BF) CSI-RS or Class B eMIMO-Type with K₁≧1 resources may beused. In another example, the “second NZP CSI-RS resource” correspondsto a BF CSI-RS or Class B eMIMO-Type with either K₂=1 resource or K₂>1resources.

In some embodiments, the configured first CSI-RS has one component foreach of the two dimensions. For 1D antenna port configurations, thefirst CSI-RS has one component, and for 2D antenna port configurations,the first CSI-RS has two components, for example, a first CSI-RS 1 or afirst CSI-RS component 1, and a first CSI-RS 2 or a first CSI-RScomponent 2.

In some embodiments, the configured second CSI-RS has one component foreach of the two dimensions. For 1D antenna port configurations, thesecond CSI-RS has one component, and for 2D antenna port configurations,the second CSI-RS has two components, for example, a second CSI-RS 1 orsecond CSI-RS component 1, and a second CSI-RS 2 or second CSI-RScomponent 2.

In some embodiments, the full-port first CSI-RS resource is alsoreferred to as Class A CSI-RS or eMIMO-Type, the partial-port firstCSI-RS resource is also referred to as Class B (K>1) CSI-RS oreMIMO-Type, and the second CSI-RS resource is also referred to as ClassB CSI-RS or eMIMO-Type.

In LTE specification, the following CSI reporting types or eMIMO-Typeare supported: ‘Class A’ eMIMO-Type in which “First CSI-RS resource” isfull-port, NP and CSI is reported using Class A codebook; and ‘Class B’eMIMO-Type in which “Second CSI-RS resource” is beamformed and CSI isreported using Class B codebook. In such embodiments, the followingparameters are determined, K=1: CQI, PMI, RI feedback and K>1: CRI, CQI,PMI, RI feedback.

FIG. 14 illustrates an example Class A channel state information (CSI)feedback scheme 1400 according to embodiments of the present disclosure.An embodiment of the Class A CSI feedback scheme 1400 shown in FIG. 14is for illustration only. One or more of the components illustrated inFIG. 14 can be implemented in specialized circuitry configured toperform the noted functions or one or more of the components can beimplemented by one or more processors executing instructions to performthe noted functions. Other embodiments are used without departing fromthe scope of the present disclosure.

In LTE specification ‘Class A’ eMIMO-Type, a UE is configured with a CSIprocess comprising of a “first” CSI-RS resource for all 2N₁N₂ ports.Upon receiving the CSI-RS for these ports, the UE derives and feeds backthe Class A CSI feedback content comprising of the first PMI index pair,(i_(1,1), i_(1,2)), the second PMI index i₂, CQI, and RI. An exemplaryuse case of the Class A CSI feedback scheme is described in FIG. 14. TheUE derives the two PMIs using the Class A PMI codebook.

FIG. 15 illustrates an example Class B CSI feedback scheme 1500according to embodiments of the present disclosure. An embodiment of theClass B CSI feedback scheme 1500 shown in FIG. 15 is for illustrationonly. One or more of the components illustrated in FIG. 15 can beimplemented in specialized circuitry configured to perform the notedfunctions or one or more of the components can be implemented by one ormore processors executing instructions to perform the noted functions.Other embodiments are used without departing from the scope of thepresent disclosure.

In LTE specification ‘Class B’ eMIMO-Type, a UE is configured with a CSIprocess comprising of a “second” CSI-RS resource for a subset of 2N₁N₂ports. For example, the number of configured ports is 2. Upon receivingthe CSI-RS for these ports, the UE derives and feeds back the Class BCSI feedback content comprising of a single PMI i, CQI, and RI. Anexemplary use case of the Class B CSI feedback scheme is described inFIG. 15. The UE derives the PMI using the Class B PMI codebook.

Note that the CSI-RS overhead with the Class A CSI feedback scheme islarge, which may lead to performance loss. The overhead is small forClass B CSI feedback scheme, but it relies on the availability ofbeam-forming weights to beam-form Class B CSI-RS. The beam-formingweights may be obtained from UL SRS measurements assuming UL-DL duplexdistance is small. Alternatively, it may be obtained through a Class Afeedback configured with larger periodicity. The later alternative is anexample of “Hybrid” CSI feedback scheme.

An issue with the Class A CSI feedback scheme for the future generationof communication system, is the increase in CSI-RS overhead to supportlarger number of antenna ports. In particular, as the number ofsupported antenna ports increases beyond a certain number, i.e. 32, theycan't be transmitted and measured in the same subframe. Hence, CSI-RStransmission and reception may require multiple subframes, which may notbe desirable in practice.

Another issue with the Class A CSI feedback scheme is that the increasein overhead is unclear to bring justifiable performance benefits. Inother words, to achieve certain performance, it may not be necessary totransmit CSI-RS from all 2N₁N₂ ports in every CSI-RS transmissioninstance as is the case with Class A CSI feedback scheme. The sameperformance may perhaps be achieved by a so-called “hybrid CSI feedbackscheme” in which there are two types of CSI-RS resources, the firstCSI-RS resource is transmitted from all or a subset of 2N₁N₂ ports witha larger periodicity and the second CSI-RS resource is transmitted fromfewer than 2N₁N₂ ports, e.g. 2, with a smaller periodicity. The twoCSI-RS resources are associated with two CSI reporting or eMIMO-Types.

In some embodiments, a UE is configured with either one CSI process withtwo NZP CSI-RS resources (each of the two associated with an eMIMO-Type)or two CSI processes each with one NZP CSI-RS resource associated withan eMIMO-Type, where 1st CSI-RS resource is associated with either ClassA eMIMO-Type or Class B eMIMO-Type with K₁≧1 resource. In this instanceof use cases, these two alternatives correspond to non-precoded (NP)CSI-RS and partial-port CSI-RS, respectively. And wherein 2nd CSI-RSresource is associated with Class B eMIMO-Type with K₂≧1 resources.

The two NZP CSI-RS resources are associated with two eMIMO-Typesaccording to the configuration where examples of supported eMIMO-Typecombinations are according to Table 3. The RI reported in the 1steMIMO-Type is denoted as RI⁽¹⁾ and that reported in the 2nd eMIMO-Typeis denoted as RI⁽²⁾. Some of these configurations such as Configuration0 have multiple alternatives such as a, b, and c depending on CSIreporting contents. In one embodiment, one of these alternatives isconfigured to the UE via higher-layer RRC signaling. In anotherembodiment, the alternative is fixed, for example, 0-a, and hence doesnot need to be configured.

TABLE 3 Supported eMIMO-Type combinations for hybrid CSI reporting CSIderived with the first CSI derived with the second CSI-RS resource (BF)CSI-RS resource eMIMO- CSI eMIMO- CSI Configuration Type reportingcontent Type reporting content 0 0-a Class A i₁ or (i_(1,1), i_(1,2)),RI⁽¹⁾ Class B CQI, PMI 0-b i₁ or (i_(1,1), i_(1,2)) K₂ = 1 RI⁽²⁾, CQI,PMI 0-c i₁ or (i_(1,1), i_(1,2)), RI⁽¹⁾ RI⁽²⁾, CQI, PMI 1 1-a Class BPMI (Alt0: Rel. 13 Class Class B RI⁽²⁾, CQI, PMI K₁ =1 B codebook Alt1:Rel. 12 K₂ = 1 codebooks) 1-b CQI, RI⁽¹⁾, PMI (Alt0: RI⁽²⁾, CQI, PMIRel. 13 Class B codebook Alt 1: Rel. 12 codebooks) 2 2-a Class B CRIClass B RI⁽²⁾, CQI, PMI 2-b K₁ > 1 PMI (Alt0: Rel. 13 Class K₂ = 1RI⁽²⁾, CQI, PMI B codebook Alt1: Rel. 12 codebooks)/RI⁽¹⁾ for eachCSI-RS resource 3 3-a Class B i₁ or (i_(1,1), i_(1,2)) Class B CRI, and{RI⁽²⁾, CQI, K₁ = 1 K₂ > 1 PMI} conditioned on CRI 4 3-a Class A i₁ or(i_(1,1), i_(1,2)) Class B CRI, and {RI⁽²⁾, CQI, K₂ > 1 PMI} conditionedon CRI 3-b i₁ or (i_(1,1), i_(1,2)), RI⁽¹⁾ CRI, and {RI⁽²⁾, CQI, PMI}conditioned on CRI

In some embodiments, a UE is configured with a hybrid CSI reporting inwhich the first eMIMO-Type is Class A and the second eMIMO-Type is ClassB, K=1. The CSI reported in Class A eMIMO-Type includes i₁ or (i_(1,1),i_(1,2)) and Class B, K=1 eMIMO-Type includes CQI, PMI, and RI⁽²⁾.

In some embodiments, a UE is configured to report periodic the hybridCSI, according to Configuration 0-b, such that the reporting interval ofthe first eMIMO-Type (Class A) is a multiple of one of the reports ofthe second eMIMO-Type with the offset parameterN_(OFFSET,PMI)=N_(OFFSET,ClassA), which is configured to the UE.

In the case where wideband CQI/PMI reporting is configured: for a UEconfigured in transmission mode 9 or 10, and UE configured with thefirst eMIMO-Type and the second eMIMO-Type by higher layers, and firsteMIMO-Type set to ‘CLASS A’ and second eMIMO-Type set to ‘CLASS B’ withK=1 resource; the reporting instances for wideband CQI/PMI of secondeMIMO-Type are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI))mod(N_(pd))=0; the reporting intervalof the RI reporting of second eMIMO-Type is an integer multiple M_(RI)of period N_(pd) (in subframes), where the reporting instances for RIare subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI))mod(N_(pd)·M_(RI))=0;and the reporting interval of wideband first PMI of first eMIMO-Typereporting is according to one of the following alternatives: (Alt 0) Thereporting instances for wideband first PMI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA))mod(H′·M_(RI))=0,wherein in Alt 0-5, the reporting interval of wideband first PMI is aninteger multiple M_(PMI)=H′ of period N_(pd) or M_(RI) or N_(pd)·M_(RI)(in subframes).

The periodic CSI reporting using PUCCH Mode 1-1, Submode 1 and Submode2, respectively, is summarized in Table 4 and Table 5. The two equationsin Alt 0-5 are equivalent if we set M_(PMI)=H′ andN_(OFFSET,PMI)=N_(OFFSET,ClassA).

TABLE 4 Periodic CSI reporting for Configuration 0-b: PUCCH Mode 1-1,Submode 1 Mode 1-1: eMIMO- Reporting Periodicity Submode 1 Type type andoffset PMI i₁ or (i_(1,1), i_(1,2)) First (Class A) Type 2a Alt 0, Alt1, Alt 2, Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′ · M_(RI) ·N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,PMI))mod(M_(PMI) · M_(RI) · N_(pd)) = 0 Alt 1:(10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA))mod(H′ ·M_(RI) · N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,PMI))mod(M_(PMI) · M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) +└n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′· N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,PMI))mod(M_(PMI) · N_(pd)) = 0 Alt 3: (10 ×n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA))mod(H′ ·N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,PMI))mod(M_(PMI) · N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′ · M_(RI))= 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,PMI))mod(M_(PMI) · M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA))mod(H′ · M_(RI)) = 0 or (10 ×n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,PMI))mod(M_(PMI) ·M_(pd)) = 0 Mode 1-1: eMIMO-type Reporting Submode 1 Second Type RI/WBPMI1 (Class B, K = 1) Type 5 Periodcity and offset (10 × n_(f) + └n_(s)/ 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1:eMIMO-type Reporting Submode 1 Second Type WB CQI/PMI2 (Class B, K = 1)Type 2b Periodcity and offset (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

TABLE 5 Periodic CSI reporting for Configuration 0-b: PUCCH Mode 1-1,Submode 2 Mode 1-1: eMIMO- Reporting Periodicity and offset Submode 1Type type Alt 0, Alt 1, Alt 2, PMI i₁ or (i_(1,1), i_(1,2)) First (ClassA) Type 2a Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′ · M_(RI) ·N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,PMI))mod(M_(PMI) · M_(RI) · N_(pd)) = 0 Alt 1:(10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA))mod(H′ ·M_(RI) · N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,PMI))mod(M_(PMI) · M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) +└n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′· N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,PMI))mod(M_(PMI) · N_(pd)) = 0 Alt 3: (10 ×n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA))mod(H′ ·N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,PMI))mod(M_(PMI) · N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′ · M_(RI))= 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,PMI))mod(M_(PMI) · M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA))mod(H′ · M_(RI)) = 0 or (10 ×n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,PMI))mod(M_(PMI) ·M_(pd)) = 0 Mode 1-1: eMIMO-Type Reporting Submode 1 Second type RI(Class B, K = 1) Type 3 Periodicity and offset (10 × n_(f) + └n_(s) / 2┘− N_(OFFSET,CQI) − N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1:eMIMO- Submode 1 Type Reporting WB Second type CQI/PMI1/PMI2 (Class B, K= 1) Type 2b Periodicity and offset (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

In some embodiments, a UE is configured with a hybrid CSI reporting inwhich the 1st eMIMO-Type is Class A and the 2nd eMIMO-Type is Class B,K=1. The CSI reported in Class A eMIMO-Type includes i₁ or (i_(1,1),i_(1,2)), and RI⁽¹⁾ and Class B eMIMO-Type includes CQI, PMI, and RI⁽²⁾.

In some embodiments, a UE is configured to report periodic the hybridCSI, according to Configuration 0-c and when both i₁ or (i_(1,1),i_(1,2)), and RI⁽¹⁾ are reported jointly in the same PUCCH reportinginstances, such that the reporting interval both i₁ or (i_(1,1),i_(1,2)), and RI⁽¹⁾ of the first eMIMO-Type (Class A) is a multiple ofone of the reports of the second eMIMO-Type with the offset parameterN_(OFFSET,PMI/RI)=N_(OFFSET,ClassA), which is configured to the UE.

In the case where wideband CQI/PMI reporting is configured: for a UEconfigured in transmission mode 9 or 10, and UE configured with thefirst eMIMO-Type and the second eMIMO-Type by higher layers, and firsteMIMO-Type set to ‘CLASS A’ and second eMIMO-Type set to ‘CLASS B’ withK=1 resource; the reporting instances for wideband CQI/PMI of secondeMIMO-Type are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI))mod(N_(pd))=0; the reporting intervalof the RI reporting of second eMIMO-Type is an integer multiple M_(RI)of period N_(pd) (in subframes), where the reporting instances for RIare subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI))mod(N_(pd)·M_(RI))=0;and the reporting interval of wideband first PMI and RI of firsteMIMO-Type reporting is according to one of the following alternatives,where: (Alt 0) The reporting instances for wideband first PMI and RI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for wideband first PMI and RI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for wideband first PMI and RI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for wideband first PMI and RI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for wideband first PMI and RI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for wideband first PMI and RI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA))mod(H′·M_(RI))=0,wherein in Alt 0-5, the reporting interval of wideband first PMI and RIis an integer multiple M_(PMI/RI)=H′ of period N_(pd) or M_(RI) orN_(Pd)·M_(RI) (in subframes).

The periodic CSI reporting using PUCCH Mode 1-1, Submode 1 and Submode2, respectively, is summarized in Table 6 and Table 7. The two equationsin Alt 0-5 are equivalent if we set M_(PMI/RI)=H′ andN_(OFFSET,PMI/RI)=N_(OFFSET,ClassA).

TABLE 6 Periodic CSI reporting for Configuration 0-c: PUCCH Mode 1-1,Submode 1 Mode 1-1: eMIMO- Reporting Submode 1 Type type RI/PMI i₁ orFirst Type Periodicity and offset (i_(1,1), i_(1,2)) (Class A) 5 Alt 0,Alt 1, Alt 2, Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′ · M_(RI) ·N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,PMI/RI))mod(M_(PMI/RI) · M_(RI) · N_(pd)) = 0Alt 1: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA))mod(H′ · M_(RI) · N_(pd)) = 0 or (10 × n_(f) + └n_(s)/ 2┘ − N_(OFFSET,CQI) − N_(OFFSET,PMI))mod(M_(PMI) · M_(RI) · N_(pd)) =0 Alt 2: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassA))mod(H′ · N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,PMI,RI))mod(M_(PMI/RI) ·N_(pd)) = 0 Alt 3: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA))mod(H′ · N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,PMI/RI))mod(M_(PMI/RI) · N_(pd)) = 0 Alt 4:(10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassA))mod(H′ · M_(RI)) = 0 or (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,PMI/RI))mod(M_(PMI/RI) ·M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA))mod(H′ · M_(RI)) = 0 or (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,PMI/RI))mod(M_(PMI/RI) · M_(pd)) = 0 Mode1-1: eMIMO- Submode 1 Type Reporting RI/WB Second type PMI1 (Class B, K= 1) Type 5 Periodicity and offset (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1: eMIMO-Submode 1 Type Reporting WB Second type CQI/PMI2 (Class B, K = 1) Type2b Periodicity and offset (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

TABLE 7 Periodic CSI reporting for Configuration 0-c: PUCCH Mode 1-1,Submode 2 Mode 1-1: eMIMO- Submode 2 Type Reporting RI/PMI i₁ or Firsttype Periodicity and offset (i_(1,1), i_(1,2)) (Class A) Type 5 Alt 0,Alt 1, Alt 2, Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′ · M_(RI) ·N_(pd)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,PMI/RI))mod(M_(PMI/RI) · M_(RI) · N_(pd)) = 0Alt 1: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA))mod(H′ · M_(RI) · N_(pd)) = 0 or (10 × n_(f) + └n_(s)/ 2┘ − N_(OFFSET,CQI) − N_(OFFSET,PMI/RI))mod(M_(PMI/RI) · M_(RI) ·N_(pd)) = 0 Alt 2: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′ · N_(pd)) = 0 or (10 × n_(f) +└n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,PMI,RI))mod(M_(PMI/RI) · N_(pd)) = 0 Alt 3: (10 × n_(f) +└n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA))mod(H′ · N_(pd)) = 0 or(10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,PMI/RI))mod(M_(PMI/RI) · N_(pd)) = 0 Alt 4: (10 × n_(f) +└n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA))mod(H′· M_(RI)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,PMI/RI))mod(M_(PMI/RI) · M_(RI)) = 0 Alt 5:(10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA))mod(H′ ·M_(RI)) = 0 or (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,PMI/RI))mod(M_(PMI/RI) · M_(RI)) = 0 eMIMO- Mode 1-1: TypeReporting Submode 2 Second 2 type RI (Class B, K = 1) Type 3 Periodicityand offset (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1: eMIMO- Submode 2 TypeReporting WB Second 2 type CQI/PMI1/PMI2 (Class B, K = 1) Type 2bPeriodicity and offset (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

As an example, the periodicity M_(PMI/RI), and relative offsetN_(OFFSET,PMI/RI) for wideband first PMI and RI reporting are determinedbased on the higher layer parameter pmi-ri-ConfigIndex (I_(PMI/RI))given in Table 7-1 below.

TABLE 7-1 Mapping of I_(PMI/RI) to M_(PMI/RI) and N _(OFFSET,PMI/RI)Value of I_(PMI/RI) M_(PMI/RI) Value of N_(OFFSET,PMI/RI)  0 ≦I_(PMI/RI) ≦ 160 1 −I_(PMI/RI) 161 ≦ I_(PMI/RI) ≦ 321 2 −(I_(PMI/RI) −161) 322 ≦ I_(PMI/RI) ≦ 482 4 −(I_(PMI/RI) − 322) 483 ≦ I_(PMI/RI) ≦ 6438 −(I_(PMI/RI) − 483) 644 ≦ I_(PMI/RI) ≦ 804 16 −(I_(PMI/RI) − 644) 805≦ I_(PMI/RI) ≦ 965 32 −(I_(PMI/RI) − 805)  966 ≦ I_(PMI/RI) ≦ 1023Reserved

In some embodiments, a UE is configured to report periodic the hybridCSI, according to Configuration 0-c and when i₁ or (i_(1,1), i_(1,2)),and RI⁽¹⁾ are reported separately in two different PUCCH reportinginstances. In one example, i₁ or (i_(1,1), i_(1,2)) of the firsteMIMO-Type (Class A) is a multiple of one of the reports of the secondeMIMO-Type with the offset parameter N_(OFFSET,ClassA,PMI), which isconfigured to the UE. In another example, RI⁽¹⁾ of the first eMIMO-Type(Class A) is a multiple of one of the reports of the second eMIMO-Typewith the offset parameter N_(OFFSET,ClassA,RI), which is configured tothe UE.

In some embodiments, the offsets of PMI and RI of first eMIMO-Type arerelative to the second eMIMO-Type. In such embodiments, wideband CQI/PMIreporting is configured, for example, for a UE configured intransmission mode 9 or 10, and UE configured with the first eMIMO-Typeand the second eMIMO-Type by higher layers, and first eMIMO-Type set to‘CLASS A’ and second eMIMO-Type set to ‘CLASS B’ with K=1 resource. Inone example, the reporting instances for wideband CQI/PMI of secondeMIMO-Type are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI))mod(N_(pd))=0. In another example,the reporting interval of the RI reporting of second eMIMO-Type is aninteger multiple M_(RI) of period N_(pd) (in subframes). In suchexample, the reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI))mod(N_(pd)·M_(RI))=0.

In yet another example, the reporting interval of wideband first PMI offirst eMIMO-Type reporting is according to one of the followingalternatives: (Alt 0) The reporting instances for wideband first PMI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA,PMI))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA,PMI))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA,PMI))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA,PMI))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA,PMI))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA,PMI))mod(H′·M_(RI))=0.

In yet another example, the reporting interval of RI of first eMIMO-Typereporting is according to one of the following alternatives: (Alt 0) Thereporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA,RI))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA,RI))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA,RI))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA,RI))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for RI are subframes satisfying; and(Alt 5) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA,RI))mod(H′·M_(RI))=0.

The periodic CSI reporting using PUCCH Mode 1-1, Submode 1 and Submode2, respectively, is summarized in Table 8 and Table 9.

TABLE 8 Periodic CSI reporting for configuration 0-c: PUCCH Mode 1-1,submode 1 Mode 1-1: eMIMO- Submode 1 Type Reporting PMI i₁ or First typePeriodicity and offset (i_(1,1), i_(1,2)) (Class A) Type 2a Alt 0, Alt1, Alt 2, Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA,PMI))mod(H′ · M_(RI) ·N_(pd)) = 0 Alt 1: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA,PMI))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) +└n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassA,PMI))mod(H′ · N_(pd)) = 0 Alt 3: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA,PMI))mod(H′ · N_(pd)) = 0 Alt 4:(10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassA,PMI))mod(H′ · M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA,PMI))mod(H′ · M_(RI)) = 0 Mode1-1: eMIMO- Reporting Submode 1 Type type Periodicity and offset RIFirst (Class A) Type 3 Alt 0, Alt 1, Alt 2, Alt 3, Alt 4, Alt 5 Alt 0:(10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassA,RI))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 1: (10 × n_(f) +└n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA,RI))mod(H′ · M_(RI) ·N_(pd)) = 0 Alt 2: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassA,RI))mod(H′ · N_(pd)) = 0 Alt 3: (10 ×n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA,RI))mod(H′ ·N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassA,RI))mod(H′ · M_(RI)) = 0 Alt 5: (10 ×n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA,RI))mod(H′ ·M_(RI)) = 0 Mode 1-1: eMIMO- Submode 1 Type Reporting RI/WB Second typePeriodicity and offset PMI1 (Class B, K = 1) Type 5 Alt 0, Alt 1, Alt 2,Alt 3, Alt 4, Alt 5 (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1: eMIMO- Submode 1 TypeReporting WB Second type CQI/PMI2 (Class B, K = 1) Type 2b Periodicityand offset (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI))mod(N_(pd)) = 0

TABLE 9 Periodic CSI reporting for configuration 0-c: PUCCH Mode 1-1,submode 2 Mode 1-1: eMIMO- Submode 2 Type Reporting RI/PMI i₁ or Firsttype Periodicity and offset (i_(1,1), i_(1,2)) (Class A) Type 5 Alt 0,Alt 1, Alt 2, Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA,PMI))mod(H′ · M_(RI) ·N_(pd)) = 0 Alt 1: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA,PMI))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) +└n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassA,PMI))mod(H′ · N_(pd)) = 0 Alt 3: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA,PMI))mod(H′ · N_(pd)) = 0 Alt 4:(10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassA,PMI))mod(H′ · M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA,PMI))mod(H′ · M_(RI)) = 0 Mode1-1: eMIMO- Reporting Submode 2 Type type RI First (Class A) Type 3Periodicity and offset Alt 0: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI)− N_(OFFSET,RI) − N_(OFFSET,ClassA,RI))mod(H′ · M_(RI) · N_(pd)) = 0 Alt1: (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA,RI))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) +└n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassA,RI))mod(H′ · N_(pd)) = 0 Alt 3: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA,RI))mod(H′ · N_(pd)) = 0 Alt 4:(10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassA,RI))mod(H′ · M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s) /2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassA,RI))mod(H′ · M_(RI)) = 0 eMIMO-Mode 1-1: Type Reporting Submode 2 Second type RI (Class B, K = 1) Type3 Periodicity and offset (10 × n_(f) + └n_(s) / 2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1: eMIMO- Submode 2 TypeReporting WB Second type CQI/PMI1/PMI2 (Class B, K = 1) Type 2bPeriodicity and offset (10 × n_(f) + └n_(s) / 2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

In some embodiments, the offsets of PMI and RI of first eMIMO-Type arerelative to each other. For example, offset of PMI is relative to thatof RI. In such embodiments, wideband CQI/PMI reporting is configured,for example, for a UE configured in transmission mode 9 or 10, and UEconfigured with the first eMIMO-Type and the second eMIMO-Type by higherlayers, and first eMIMO-Type set to ‘CLASS A’ and second eMIMO-Type setto ‘CLASS B’ with K=1 resource. In another example, the reportinginstances for wideband CQI/PMI of second eMIMO-Type are subframessatisfying (10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI))mod(N_(pd))=0. In yetanother example, the reporting interval of the RI reporting of secondeMIMO-Type is an integer multiple M_(RI) of period N_(pd) (insubframes). In such example, the reporting instances for RI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI))mod(N_(pd)·M_(RI))=0.

In yet another example, the reporting interval of wideband first PMI offirst eMIMO-Type reporting is according to one of the followingalternatives: (Alt 0) The reporting instances for wideband first PMI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassA,RI)−N_(OFFSET,ClassA,PMI))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassA,RI)−N_(OFFSET,ClassA,PMI))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassA,RI)−N_(OFFSET,ClassA,PMI))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassA,RI)−N_(OFFSET,ClassA,PMI))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassA,RI)−N_(OFFSET,ClassA,PMI))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for wideband first PMI are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassA,RI)−N_(OFFSET,ClassA,PMI))mod(H′·M_(RI))=0.

In yet another example, the reporting interval of RI of first eMIMO-Typereporting is according to one of the following alternatives: (Alt 0) Thereporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA,RI))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA,RI))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA,RI))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassA,RI))mod(H′·n_(PD))=0;(Alt 4) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassA,RI))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)N_(OFFSET,ClassA,RI))mod(H′·M_(RI))=0.

The periodic CSI reporting using PUCCH Mode 1-1, Submode 1 and Submode2, respectively, is summarized in Table 10 and Table 11.

TABLE 10 Periodic CSI reporting configuration 0-c: PUCCH Mode 1-1,Submode 1 Mode 1-1: eMIMO- Reporting Periodicity Submode 1 Type type andoffset PMI i₁ or First Alt 0, Alt 1, Alt 2, (i_(1,1),i_(1,2)) (Class A)Type 2a Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,ClassA,RI) − N_(OFFSET,ClassA,PMI))mod (H′ · M_(RI) · N_(pd))= 0 Alt 1: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassA,RI) −N_(OFFSET,ClassA,PMI))mod (H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassA,RI) − N_(OFFSET,ClassA,PMI))mod (H′· N_(pd)) = 0 Alt 3: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassA,RI) −N_(OFFSET,ClassA,PMI))mod (H′ · N_(pd)) = 0 Alt 4: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,ClassA,RI) − N_(OFFSET,ClassA,PMI))mod (H′ ·M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassA,RI) −N_(OFFSET,ClassA,PMI))mod (H′ · M_(RI)) = 0 Mode 1-1: eMIMO- ReportingPeriodicity Submode 1 Type type and offset First Type Alt 0, Alt 1, Alt2, RI (Class A) 3 Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA,RI))mod(H′ · M_(RI) ·N_(pd)) = 0 Alt 1: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA,RI))mod (H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA,RI))mod(H′ · N_(pd)) = 0 Alt 3: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA,RI))mod (H′ · N_(pd)) = 0 Alt 4: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA,RI))mod(H′ · M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA,RI))mod (H′ · M_(RI)) = 0 Mode 1-1: ReportingPeriodicity Submode 1 eMIMO-Type type and offset RI/WB Second PMI1(Class B, K = 1) Type 5 (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1: Reporting PeriodicitySubmode 1 eMIMO-Type type and offset WB Second CQI/PMI2 (Class B, K = 1)Type 2b (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI))mod(N_(pd)) = 0

TABLE 11 Periodic CSI reporting configuration 0-c: PUCCH Mode 1-1.Submode 2. Mode 1-1: eMIMO- Reporting Periodicity Submode 2 Type typeand offset RI/PMI i₁ or First Alt 0, Alt 1, Alt 2, (i_(1,1),i_(1,2))(Class A) Type 5 Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,ClassA,RI) − N_(OFFSET,ClassA,PMI))mod (H′ · M_(RI) · N_(pd))= 0 Alt 1: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassA,RI) −N_(OFFSET,ClassA,PMI))mod (H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassA,RI) − N_(OFFSET,ClassA,PMI))mod (H′· N_(pd)) = 0 Alt 3: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassA,RI) −N_(OFFSET,ClassA,PMI))mod (H′ · N_(pd)) = 0 Alt 4: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,ClassA,RI) − N_(OFFSET,ClassA,PMI))mod (H′ ·M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassA,RI) −N_(OFFSET,ClassA,PMI))mod (H′ · M_(RI)) = 0 Mode 1-1: eMIMO- ReportingPeriodicity Submode 2 Type type and offset First Alt 0, Alt 1, Alt 2, RI(Class A) Type 3 Alt 3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA,RI) )mod(H′ · M_(RI) ·N_(pd)) = 0 Alt 1: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA,RI))mod (H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA,RI))mod(H′ · N_(pd)) = 0 Alt 3: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA,RI))mod (H′ · N_(pd)) = 0 Alt 4: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) − N_(OFFSET,ClassA,RI))mod(H′ · M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassA,RI))mod (H′ · M_(RI)) = 0 Mode 1-1: ReportingPeriodicity Submode 2 eMIMO-Type type and offset Second RI (Class B, K= 1) Type 3 (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1: Reporting PeriodicitySubmode 2 eMIMO-Type type and offset WB Second CQI/PMI1/ (Class B, PMI2K = 1) Type 2b (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI))mod(N_(pd)) = 0

In some embodiments, a UE is configured with a hybrid CSI reporting inwhich the 1st eMIMO-Type is Class B, K₁=2 and the 2nd eMIMO-Type isClass B, K₂=1. The CSI reported in: Class B, K₁=2 eMIMO-Type is PMI(assuming RI=1) for each CSI-RS resource; or Class B, K₂=1 eMIMO-Typeincludes RI⁽²⁾, CQI, and PMI.

In some embodiments, a UE is configured to report periodic hybrid CSI,according to Configuration 2 and when PMI1 and PMI2 associated with tworesources of first eMIMO-Type are reported jointly in the same PUCCHreporting instances, such that the reporting interval PMI1 and PMI2 ofthe first eMIMO-Type (Class B, K=2) is a multiple of one of the reportsof the second eMIMO-Type (Class B, K=1) with the offset parameterN_(OFFSET,ClassB), which is configured to the UE.

In such embodiments, wideband CQI/PMI reporting is configured, forexample, for a UE configured in transmission mode 9 or 10, and UEconfigured with the first eMIMO-Type and the second eMIMO-Type by higherlayers, and first eMIMO-Type set to ‘CLASS B’ with K=2 resources andsecond eMIMO-Type set to ‘CLASS B’ with K=1 resource. In anotherexample, the reporting instances for wideband CQI/PMI of secondeMIMO-Type are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI))mod(N_(pd))=0. In yet anotherexample, the reporting interval of the RI reporting of second eMIMO-Typeis an integer multiple M_(RI) of period N_(pd) (in subframes). In suchexample, the reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI))mod(N_(pd)·M_(RI))=0.

In yet another example, the reporting interval of wideband PMI1 and PMI2of first eMIMO-Type reporting is according to one of the followingalternatives: (Alt 0) The reporting instances for wideband PMI1 and PMI2are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for wideband PMI1 and PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for wideband PMI1 and PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for wideband PMI1 and PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for wideband PMI1 and PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for wideband PMI1 and PMI2 aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB))mod(H′·M_(RI))=0.

The periodic CSI reporting using PUCCH Mode 1-1, Submode 1 and Submode2, respectively, is summarized in Table 12 and Table 13.

TABLE 12 Periodic CSI reporting configuration 2: PUCCH Mode 1-1. Submode1 Mode 1-1: eMIMO- Reporting Periodicity Submode 1 Type type and offsetPMI1/ First Alt 0, Alt 1, Alt 2, PMI2 (Class B, K = 2) Type 2a Alt 3,Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassB))mod (H′ · M_(RI) · N_(pd)) = 0 Alt 1:(10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassB))mod (H′ ·M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassB))mod (H′ · N_(pd)) = 0 Alt 3: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassB))mod (H′ · N_(pd))= 0 Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassB))mod (H′ · M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI) − N_(OFFSET,ClassB))mod (H′ · M_(RI)) = 0 Mode 1-1:eMIMO- Reporting Periodicity Submode 1 Type type and offset RI/WB SecondPMI1 (Class B, K = 1) Type 5 (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1: Reporting PeriodicitySubmode 1 eMIMO-Type type and offset WB Second CQI/PMI2 (Class B, K = 1)Type 2b (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI))mod(N_(pd)) = 0

TABLE 13 Periodic CSI reporting configuration 2: PUCCH Mode 1-1. Submode2 Mode 1-1: eMIMO- Reporting Periodicity Submode 2 Type type and offsetPMI1/ First Alt 0, Alt 1, Alt 2, PMI2 (Class B, K = 2) Type 2a Alt 3,Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassB))mod (H′ · M_(RI) · N_(pd)) = 0 Alt 1:(10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassB))mod (H′ ·M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassB))mod (H′ · N_(pd)) = 0 Alt 3: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassB))mod (H′ · N_(pd))= 0 Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassB))mod (H′ · M_(RI)) = 0 Alt 5: (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI) − N_(OFFSET,ClassB))mod (H′ · M_(RI)) = 0 Mode 1-1:eMIMO- Reporting Periodicity Submode 2 Type type and offset Second RI(Class B, K = 1) Type 3 (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1: eMIMO- ReportingPeriodicity Submode 2 Type type and offset WB CQI/ Second PMI1/PMI2(Class B, K = 1) Type 2b (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

In some embodiments, a UE is configured to report periodic hybrid CSI,according to Configuration 2 and when PMI1 and PMI2 associated with tworesources of first eMIMO-Type are reported in two different PUCCHreporting instances, such that the reporting interval of: PMI1 of thefirst eMIMO-Type (Class B, K=2) is a multiple of one of the reports ofthe second eMIMO-Type with the offset parameter N_(OFFSET,ClassB,PMI1),which is configured to the UE; or PMI2 the first eMIMO-Type (Class B,K=2) is a multiple of one of the reports of the second eMIMO-Type withthe offset parameter N_(OFFSET,ClassB,PMI2), which is configured to theUE.

In some embodiments, the offsets of PMI1 and PMI2 of first eMIMO-Typeare relative to the second eMIMO-Type. In such embodiments, widebandCQI/PMI reporting is configured, for example, for a UE configured intransmission mode 9 or 10, and UE configured with the first eMIMO-Typeand the second eMIMO-Type by higher layers, and first eMIMO-Type set to‘CLASS B’ with K=2 resources and second eMIMO-Type set to ‘CLASS B’ withK=1 resource.

In one example, the reporting instances for wideband CQI/PMI of secondeMIMO-Type are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI))mod(N_(pd))=0.

In yet another example, the reporting interval of the RI reporting ofsecond eMIMO-Type is an integer multiple M_(RI) of period N_(pd) (insubframes). In such example, the reporting instances for RI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI))mod(N_(pd)·M_(RI))=0.

In yet another example, the reporting interval of wideband PMI1 of firsteMIMO-Type reporting is according to one of the following alternatives:(Alt 0) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB,PMI1))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB,PMI1))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB,PMI1))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB,PMI1))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB,PMI1))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB,PMI1))mod(H′·M_(RI))=0.

In yet another example, the reporting interval of wideband PMI2 of firsteMIMO-Type reporting is according to one of the following alternatives:(Alt 0) The reporting instances for wideband PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB,PMI2))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for wideband PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB,PMI2))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for wideband PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB,PMI2))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for wideband PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB,PMI2))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for wideband PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB,PMI2))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for wideband PMI2 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB,PMI2))mod(H′·M_(RI))=0.

The periodic CSI reporting using PUCCH Mode 1-1, Submode 1 and Submode2, respectively, is summarized in Table 14 and Table 15.

TABLE 14 Periodic CSI reporting configuration 2: PUCCH Mode 1-1. Submode1 Mode 1-1: eMIMO- Reporting Periodicity Submode 1 Type type and offsetFirst (Class B, Alt 0, Alt 1, Alt 2, PMI1 K = 2) Type 2a Alt 3, Alt 4,Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassB,PMI1))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 1: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod (H′ ·M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI1))mod(H′ · N_(pd)) = 0 Alt 3: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod (H′ ·N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI1))mod(H′ · M_(RI)) = 0 Alt 5: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod (H′ ·M_(RI)) = 0 Mode 1-1: eMIMO- Reporting Periodicity Submode 1 Type typeand offset First (Class B, PMI2 K = 2) Type 2a Alt 0: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 1: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassB,PMI2))mod (H′ ·M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI2) )mod(H′ · N_(pd)) = 0 Alt 3: (10× n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassB,PMI2))mod (H′ ·N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI2) )mod(H′ · M_(RI)) = 0 Alt 5: (10× n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassB,PMI2))mod (H′ ·M_(RI)) = 0 Mode 1-1: Reporting Periodicity Submode 1 eMIMO-Type typeand offset RI/WB Second PMI1 (Class B, K = 1) Type 5 (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode1-1: Reporting Periodicity Submode 1 eMIMO-Type type and offset WBSecond CQI/PMI2 (Class B, K = 1) Type 2b (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

TABLE 15 Periodic CSI reporting configuration 2: PUCCH Mode 1-1. Submode2 Mode 1-1: eMIMO- Reporting Periodicity Submode 2 Type type and offsetFirst (Class B, Alt 0, Alt 1, Alt 2, PMI1 K = 2) Type 2a Alt 3, Alt 4,Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassB,PMI1))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 1: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod(H′ ·M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI1))mod(H′ · N_(pd)) = 0 Alt 3: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod(H′ ·N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI1))mod(H′ · M_(RI)) = 0 Alt 5: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod(H′ ·M_(RI)) = 0 Mode 1-1: eMIMO- Reporting Periodicity Submode 2 Type typeand offset First (Class B, Alt 0, Alt 1, Alt 2, PMI2 K = 2) Type 2a Alt3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI) · N_(pd)) = 0 Alt1: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) −N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassB,PMI2) )mod(H′ · N_(pd)) = 0 Alt 3: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassB,PMI2))mod(H′ · N_(pd)) = 0Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI)) = 0 Alt 5: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI)) = 0Mode 1-1: Reporting Periodicity Submode 2 eMIMO-Type type and offsetSecond RI (Class B, K = 1) Type 3 (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1:Reporting Periodicity Submode 2 eMIMO-Type type and offset WB CQI/Second PMI1/PMI2 (Class B, K = 1) Type 2b (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

In some embodiments, the offsets of PMI1 and PMI2 of first eMIMO-Typeare relative to each other. For example, offset of PMI2 is relative tothat of PMI1. In such embodiments, wideband CQI/PMI reporting isconfigured, for example, for a UE configured in transmission mode 9 or10, and UE configured with the first eMIMO-Type and the secondeMIMO-Type by higher layers, and first eMIMO-Type set to ‘CLASS B’ withK=2 resources and second eMIMO-Type set to ‘CLASS B’ with K=1 resource.

In one example, the reporting instances for wideband CQI/PMI of secondeMIMO-Type are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI))mod(N_(pd))=0.

In yet another example, the reporting interval of the RI reporting ofsecond eMIMO-Type is an integer multiple M_(RI) of period N_(pd) (insubframes). In such example, the reporting instances for RI aresubframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI))mod(N_(pd)·M_(RI))=0.

In yet another example, the reporting interval of wideband PMI1 of firsteMIMO-Type reporting is according to one of the following alternatives:(Alt 0) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB,PMI1))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB,PMI1))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB,PMI1))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB,PMI1))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,ClassB,PMI1))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for wideband PMI1 are subframessatisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,ClassB,PMI1))mod(H′·M_(RI))=0.

In yet another example, the reporting interval of wideband PMI2 of firsteMIMO-Type reporting is according to one of the following alternatives:(Alt 0) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassB,PMI1)−N_(OFFSET,ClassB,PMI2))mod(H′·M_(RI)·N_(pd))=0;(Alt 1) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassB,PMI1)−N_(OFFSET,ClassB,PMI2))mod(H′·M_(RI)·N_(pd))=0;(Alt 2) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassB,PMI1)−N_(OFFSET,ClassB,PMI2))mod(H′·N_(pd))=0;(Alt 3) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassB,PMI1)−N_(OFFSET,ClassB,PMI2))mod(H′·N_(pd))=0;(Alt 4) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassB,PMI1)−N_(OFFSET,ClassB,PMI2))mod(H′·M_(RI))=0;and (Alt 5) The reporting instances for RI are subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,ClassB,PMI1)−N_(OFFSET,ClassB,PMI2))mod(H′·M_(RI))=0.

The periodic CSI reporting using PUCCH Mode 1-1, Submode 1 and Submode2, respectively, is summarized in Table 16 and Table 17.

TABLE 16 Periodic CSI reporting configuration 2: PUCCH Mode 1-1. Submode1 Mode 1-1: eMIMO- Reporting Periodicity Submode 1 Type type and offsetFirst (Class B, Alt 0, Alt 1, Alt 2, PMI1 K = 2) Type 2a Alt 3, Alt 4,Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassB,PMI1))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 1: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod(H′ ·M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI1))mod(H′ · N_(pd)) = 0 Alt 3: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod(H′ ·N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI1))mod(H′ · M_(RI)) = 0 Alt 5: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod(H′ ·M_(RI)) = 0 Mode 1-1: eMIMO- Reporting Periodicity Submode 1 Type typeand offset First (Class B, Alt 0, Alt 1, Alt 2, PMI2 K = 2) Type 2a Alt3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassB,PMI1)− N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 1: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) −N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) −N_(OFFSET,ClassB,PMI2))mod(H′ · N_(pd)) = 0 Alt 3: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) − N_(OFFSET,ClassB,PMI2))mod(H′ ·N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) −N_(OFFSET,ClassB,PMI2))mod(H′ · N_(pd)) = 0 Alt 5: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) − N_(OFFSET,ClassB,PMI2))mod(H′ ·N_(pd)) = 0 Mode 1-1: Reporting Periodicity Submode 1 eMIMO-Type typeand offset RI/WB Second PMI1 (Class B, K = 1) Type 5 (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode1-1: Reporting Periodicity Submode 1 eMIMO-Type type and offset WB CQI/Second PMI2 (Class B, K = 1) Type 2b (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

TABLE 17 Periodic CSI reporting configuration 2: PUCCH Mode 1-1. Submode2 Mode 1-1: eMIMO- Reporting Periodicity Submode 2 Type type and offsetFirst (Class B, Alt 0, Alt 1, Alt 2, PMI1 K = 2) Type 2a Alt 3, Alt 4,Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CQI) − N_(OFFSET,RI) −N_(OFFSET,ClassB,PMI1))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 1: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod(H′ ·M_(RI) · N_(pd)) = 0 Alt 2: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI1))mod(H′ · N_(pd)) = 0 Alt 3: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod(H′ ·N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) −N_(OFFSET,RI) − N_(OFFSET,ClassB,PMI1))mod(H′ · M_(RI)) = 0 Alt 5: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,CGI) − N_(OFFSET,ClassB,PMI1))mod(H′ ·M_(RI)) = 0 Mode 1-1: eMIMO- Reporting Periodicity Submode 2 Type typeand offset First (Class B, Alt 0, Alt 1, Alt 2, PMI2 K = 2) Type 2a Alt3, Alt 4, Alt 5 Alt 0: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassB,PMI1)− N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 1: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) −N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI) · N_(pd)) = 0 Alt 2: (10 ×n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) −N_(OFFSET,ClassB,PMI2))mod(H′ · N_(pd)) = 0 Alt 3: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) − N_(OFFSET,ClassB,PMI2))mod(H′ ·N_(pd)) = 0 Alt 4: (10 × n_(f) + └n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) −N_(OFFSET,ClassB,PMI2))mod(H′ · M_(RI)) = 0 Alt 5: (10 × n_(f) +└n_(s)/2┘ − N_(OFFSET,ClassB,PMI1) − N_(OFFSET,ClassB,PMI2))mod(H′ ·M_(RI)) = 0 Mode 1-1: Reporting Periodicity Submode 2 eMIMO-Type typeand offset Second RI (Class B, K = 1) Type 3 (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI) − N_(OFFSET,RI))mod(N_(pd) · M_(RI)) = 0 Mode 1-1:Reporting Periodicity Submode 2 eMIMO-Type type and offset WB CQI/Second PMI1/PMI2 (Class B, K = 1) Type 2b (10 × n_(f) + └n_(s)/2┘ −N_(OFFSET,CQI))mod(N_(pd)) = 0

FIG. 16 illustrates an example dual-polarized antenna port layouts for{24, 48, 96} ports 1600 according to embodiments of the presentdisclosure. An embodiment of the dual-polarized antenna port layouts for{24, 48, 96} ports 1600 shown in FIG. 16 is for illustration only. Oneor more of the components illustrated in FIG. 16 can be implemented inspecialized circuitry configured to perform the noted functions or oneor more of the components can be implemented by one or more processorsexecuting instructions to perform the noted functions. Other embodimentsare used without departing from the scope of the present disclosure.

FIG. 17 illustrates an example dual-polarized antenna port layouts for{32, 64, 128} ports 1700 according to embodiments of the presentdisclosure. An embodiment of the dual-polarized antenna port layouts for{32, 64, 128} ports 1700 shown in FIG. 17 is for illustration only. Oneor more of the components illustrated in FIG. 17 can be implemented inspecialized circuitry configured to perform the noted functions or oneor more of the components can be implemented by one or more processorsexecuting instructions to perform the noted functions. Other embodimentsare used without departing from the scope of the present disclosure.

The future generation of communication systems, such as LTE system andbeyond, and 5G, will likely to have more number of antenna ports thanthe ones currently supported by the standards. An illustration of 1D and2D antenna port layouts for {24, 48, 96} and {32, 64, 128} ports areshown in FIG. 16 and FIG. 17.

In some embodiments, a UE is configured with one or both of the twotypes of CSI-RS resources: the “first CSI-RS resource” corresponds toeither 1) full port: CSI-RS is transmitted from all 2N₁N₂ ports and itis non-precoded (NP) or partial port: CSI-RS is transmitted from asubset of 2N₁N₂ ports, and it is either i) NP CSI-RS or ii) beam-formed(BF) CSI-RS with K₁>1 resources; or the “second CSI-RS resource”corresponds to a BF CSI-RS with either 1) K₂=1 resource or 2) K₂>1resources.

In some embodiments, the configured first CSI-RS has one component foreach dimension. For 1D antenna port configurations, the first CSI-RS hasone component, and for 2D antenna port configurations, the first CSI-RShas two components first CSI-RS 1 or first CSI-RS component 1, and firstCSI-RS 2 or first CSI-RS component 2.

In some embodiments, the configured second CSI-RS has one component foreach dimension. For 1D antenna port configurations, the second CSI-RShas one component, and for 2D antenna port configurations, the secondCSI-RS has two components second CSI-RS 1 or second CSI-RS component 1,and second CSI-RS 2 or second CSI-RS component 2.

In some embodiments, a UE is configured to report at least one class ofCSI reporting or eMIMO-Type from at least four classes of CSI reportingor eMIMO-Types, Class A eMIMO-Type, Class B eMIMO-Type, Class CeMIMO-Type, and Class C′ eMIMO-Type. In Class A eMIMO-Type, the CSIcontent includes a single or a pair of 1st PMI, a single 2nd PMI, CQI,and RI. It is associated with the first or the second type of CSI-RSresource. In Class B eMIMO-Type, the CSI content includes a single PMI,CQI, and RI. In such class, it is associated with the first or thesecond type (BF) of CSI-RS resource with K resources and there are twosub-types: 1) K=1 (no CRI-RS resource indicator (CRI) feedback); and K>1including two alternatives: Alt 1: CRI is fed back; and Alt 2: Kindependent CSI reports each including at least a PMI. In Class CeMIMO-Type, the CSI content includes a single or a pair of 1st PMI,which does not include co-phase. In such Class, it is associated withthe first type (NP) of CSI-RS resource. In Class C′ eMIMO-Type, the CSIcontent includes a single or a pair of 1st PMI, which includes co-phase.In such class, it is associated with the first type (NP) of CSI-RSresource.

In some embodiments, the codebooks for different values of theeMIMO-Type are different. In this case, when the UE is configured withClass X eMIMO-Type, where X={A, B, C, C′, . . . }, the it uses thecorresponding codebook to derive CSI report.

In some embodiments, the codebooks for some values of the eMIMO-Type arethe same. In one example, the codebook for Class A and Class CeMIMO-Types are the same. In another example, the codebook for Class A,Class B, and Class C eMIMO-Types are the same. In this case, the UEderives the CSI report using the full or a part of the common codebookdepending on the configured value of eMIMO-Types.

In some embodiments, the codebooks for all values of the eMIMO-Type arethe same. For example, the codebook for eMIMO-Type=Class A, Class B,Class C, and Class C′ are the same.

In some embodiments, the full-port first CSI-RS resource is alsoreferred to as Class A CSI-RS, the partial-port first CSI-RS resource isalso referred to as Class C (or C′) CSI-RS or Class B (K>1) CSI-RS, andthe second CSI-RS resource is also referred to as Class B CSI-RS.

In LTE specification, the following CSI reporting types or eMIMO-Typeare supported: Class A eMIMO-Type in which “First CSI-RS resource” isfull-port, NP and CSI is reported using Class A codebook; and Class BeMIMO-Type in which “Second CSI-RS resource” is BF and CSI is reportedusing Class B codebook. In such Class, K=1 (no CSI feedback) or K>1 (CRIfeedback).

For transmission on two antenna ports, pε{0,1}, and for the purpose ofCSI reporting based on two antenna ports pε{0,1} or pε{15,16}, theprecoding matrix W(i) shall be selected from Table 18 or a subsetthereof. For the closed-loop spatial multiplexing transmission modedefined in LTE specification, the codebook index 0 is not used when thenumber of layers is ν=2.

TABLE 18 Codebook for transmission on antenna ports {0, 1} and for CSIreporting based on antenna ports {0, 1} or {15, 16} Codebook Number oflayers υ index 1 2 0 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\1\end{bmatrix}$ $\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 0 \\0 & 1\end{bmatrix}$ 1 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\{- 1}\end{bmatrix}$ $\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 1 \\1 & {- 1}\end{bmatrix}$ 2 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\j\end{bmatrix}$ $\frac{1}{\sqrt{2}}\begin{bmatrix}1 & 1 \\j & {- j}\end{bmatrix}$ 3 $\frac{1}{\sqrt{2}}\begin{bmatrix}1 \\{- j}\end{bmatrix}$ —

For 8 antenna ports {15,16,17,18,19,20,21,22}, 12 antenna ports{15,16,17,18,19,20,21,22,23,24,25,26}, 16 antenna ports{15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30}, and UE configuredwith higher layer parameter eMIMO-Type, and eMIMO-Type is set to ‘CLASSA’, each PMI value corresponds to three codebook, where the quantitiesφ_(n), μ_(m) and ν_(l,m) are given by:

ϕ n = e^(j π n/2) $u_{m} = \begin{bmatrix}1 & e^{j\frac{2\; \pi \; m}{O_{2}N_{2}}} & \ldots & e^{j\frac{2\; \pi \; {m{({N_{2} - 1})}}}{O_{2}N_{2}}}\end{bmatrix}$ $v_{l,m} = \begin{bmatrix}u_{m} & {e^{j\frac{2\; \pi \; l}{O_{1}N_{1}}}u_{m}} & \ldots & {e^{j\frac{2\; \pi \; {l{({N_{1} - 1})}}}{O_{1}N_{1}}}u_{m}}\end{bmatrix}^{T}$

where, the values of N₁, N₂, O₁, and O₂ are configured with thehigher-layer parameters codebook-Config-N1, codebook-Config-N2,codebook-Over-Sampling-RateConfig-O1, andcodebook-Over-Sampling-RateConfig-O2, respectively.

The supported configurations of (O₁, O₂) and (N₁, N₂) for a given numberof CSI-RS ports are given in Table 19. The number of CSI-RS ports, P, is2N₁N₂.

TABLE 19 Supported configurations of (O₁, O₂) and (N₁, N₂) Number ofCSI-RS antennaports, P (N₁, N₂) (O₁, O₂)  8 (2, 2) (4, 4), (8, 8) 12 (2,3) (8, 4), (8, 8) (3, 2) (8, 4), (4, 4) 16 (2, 4) (8, 4), (8, 8) (4, 2)(8, 4), (4, 4) (8, 1) (4, -), (8, -)

TABLE 20 Codebook for 1-layer CSI reporting using antenna ports 15 to14 + P Value of Codebook-Config. 1 i₂ i_(1,1) i_(1,2) 0 1 2 3 0, 1, . .. , O₁N₁ − 1 0, 1, . . . , O₂N₂ − 1 W_(i) _(1,1) _(,i) _(1,2) _(,0) ⁽¹⁾W_(i) _(1,1) _(,i) _(1,2) _(,1) ⁽¹⁾ W_(i) _(1,1) _(,i) _(1,2) _(,2) ⁽¹⁾W_(i) _(1,1) _(,i) _(1,2) _(,3) ⁽¹⁾${{where}\mspace{14mu} W_{l,m,n}^{(1)}} = {\frac{1}{\sqrt{P}}\begin{bmatrix}v_{l,m} \\{\phi_{n}v_{l,m}}\end{bmatrix}}$ Value of Codebook-Config. 2 i₂ i_(1,1) i_(1,2) 0 1 2 3$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2i) _(1,1)_(,2i) _(1,2) _(,0) ⁽¹⁾ W_(2i) _(1,1) _(,2i) _(1,2) _(,1) ⁽¹⁾ W_(2i)_(1,1) _(,2i) _(1,2) _(,2) ⁽¹⁾ W_(2i) _(1,1) _(,2i) _(1,2) _(,3) ⁽¹⁾ i₂i_(1,1) i_(1,2) 4 5 6 7$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2i) _(1,1)_(+1,2i) _(1,2) _(,0) ⁽¹⁾ W_(2i) _(1,1) _(+1,2i) _(1,2) _(,1) ⁽¹⁾ W_(2i)_(1,1) _(+1,2i) _(1,2) _(,2) ⁽¹⁾ W_(2i) _(1,1) _(+1,2i) _(1,2) _(,3) ⁽¹⁾i₂ i_(1,1) i_(1,2) 8 9 10 11$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2i) _(1,1)_(,2i) _(1,2) _(+1,0) ⁽¹⁾ W_(2i) _(1,1) _(,2i) _(1,2) _(+1,1) ⁽¹⁾ W_(2i)_(1,1) _(,2i) _(1,2) _(+1,2) ⁽¹⁾ W_(2i) _(1,1) _(,2i) _(1,2) _(+1,3) ⁽¹⁾i₂ i_(1,1) i_(1,2) 12  13  14 15$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2i) _(1,1)_(+1,2i) _(1,2) _(,+1,0) ⁽¹⁾ W_(2i) _(1,1) _(+1,2i) _(1,2) _(,+1,1) ⁽¹⁾W_(2i) _(1,1) _(+1,2i) _(1,2) _(,+1,2) ⁽¹⁾ W_(2i) _(1,1) _(+1,2i) _(1,2)_(,+1,3) ⁽¹⁾${{where}\mspace{14mu} W_{l,m,n}^{(1)}} = {\frac{1}{\sqrt{P}}\begin{bmatrix}v_{l,m} \\{\phi_{n}v_{l,m}}\end{bmatrix}}$ Value of Codebook-Config. 3 i₂ i_(1,1) i_(1,2) 0 1 2 3$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2x,2y,0) ⁽¹⁾W_(2x,2y,1) ⁽¹⁾ W_(2x,2y,2) ⁽¹⁾ W_(2x,2y,3) ⁽¹⁾ i₂ i_(1,1) i_(1,2) 4 5 67 $0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2x+2,2y,0)⁽¹⁾ W_(2x+2,2y,1) ⁽¹⁾ W_(2x+2,2y,2) ⁽¹⁾ W_(2x+2,2y,3) ⁽¹⁾ i₂ i_(1,1)i_(1,2) 8 9 10 11$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2x+1,2y+1,0)⁽¹⁾ W_(2x+1,2y+1,1) ⁽¹⁾ W_(2x+1,2y+1,2) ⁽¹⁾ W_(2x+1,2y+1,3) ⁽¹⁾ i₂i_(1,1) i_(1,2) 12 13 14 15$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2x+3,2y+1,0)⁽¹⁾ W_(2x+3,2y+1,1) ⁽¹⁾ W_(2x+3,2y+1,2) ⁽¹⁾ W_(2x+3,2y+1,3) ⁽¹⁾${{{where}\mspace{14mu} x} = i_{1,1}},{y = i_{1,2}},{W_{l,m,n}^{(1)} = {\frac{1}{\sqrt{P}}\begin{bmatrix}v_{l,m} \\{\phi_{n}v_{l,m}}\end{bmatrix}}},\mspace{14mu} {{{if}\mspace{14mu} N_{1}} \geq N_{2}}$${x = i_{1,2}},{y = i_{1,1}},{W_{l,m,n}^{(1)} = {\frac{1}{\sqrt{P}}\begin{bmatrix}v_{m,l} \\{\phi_{n}v_{m,l}}\end{bmatrix}}},\mspace{14mu} {{{if}\mspace{14mu} N_{1}} < N_{2}}$Value of Codebook-Config. 4 i_(1,1) i_(1,2) 4 5 6 7$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2x+1,2y,0)⁽¹⁾ W_(2x+1,2y,1) ⁽¹⁾ W_(2x+1,2y,2) ⁽¹⁾ W_(2x+1,2y,3) ⁽¹⁾ i₂ i_(1,1)i_(1,2) 8 9 10 11$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2x+2,2y,0)⁽¹⁾ W_(2x+2,2y,1) ⁽¹⁾ W_(2x+2,2y,2) ⁽¹⁾ W_(2x+2,2y,3) ⁽¹⁾ i₂ i_(1,1)i_(1,2) 12 13 14 15$0,1,\ldots \mspace{14mu},{\frac{N_{1}O_{1}}{2} - 1}$$0,1,\ldots \mspace{14mu},{\frac{N_{2}O_{2}}{2} - 1}$ W_(2x+3,2y,0)⁽¹⁾ W_(2x+3,2y,1) ⁽¹⁾ W_(2x+3,2y,2) ⁽¹⁾ W_(2x+3,2y,3) ⁽¹⁾${{{where}\mspace{14mu} x} = i_{1,1}},{y = i_{1,2}},{W_{l,m,n}^{(1)} = {\frac{1}{\sqrt{P}}\begin{bmatrix}v_{l,m} \\{\phi_{n}v_{l,m}}\end{bmatrix}}},\mspace{14mu} {{{if}\mspace{14mu} N_{1}} \geq N_{2}}$${x = i_{1,2}},{y = i_{1,1}},{W_{l,m,n}^{(1)} = {\frac{1}{\sqrt{P}}\begin{bmatrix}v_{m,l} \\{\phi_{n}v_{m,l}}\end{bmatrix}}},\mspace{14mu} {{{if}\mspace{14mu} N_{1}} < N_{2}}$

An issue with the Class A CSI feedback scheme for the future generationof communication systems (LTE system and beyond, 5G), is the increase inCSI-RS overhead to support larger number of antenna ports. Inparticular, as the number of supported antenna ports increases beyond acertain number, i.e. 32, they can't be transmitted and measured in thesame subframe. Hence, CSI-RS transmission and reception will requiremultiple subframes, which may not be desirable in practice.

Another issue with the Class A CSI feedback scheme is that the increasein overhead is unclear to bring justifiable performance benefits. Inother words, to achieve certain performance, it may not be necessary totransmit CSI-RS from all 2N₁N₂ ports in every CSI-RS transmissioninstance as is the case with Class A CSI feedback scheme. The sameperformance may perhaps be achieved by a so-called “hybrid CSI feedbackscheme” in which there are two types of CSI-RS resources, the firstCSI-RS resource is transmitted from all 2N₁N₂ ports with a largerperiodicity and the second CSI-RS resource is transmitted from fewerthan 2N₁N₂ ports, e.g. 2, with a smaller periodicity.

In some embodiments, a hybrid CSI feedback scheme is proposed in whichthe first (NP) CSI-RS resource is configured to obtain the long-term andWB channel directions or PMIs for both dimensions (azimuth andelevation).

In some embodiments, the second (BF) CSI-RS resource is beam-formedusing these channel directions before being transmitted to the UE, whichuses them to derive short-term and SB PMI together with CQI and RI.

FIG. 18 illustrates an example full port hybrid CSI feedback scheme (Alt0) 1800 according to embodiments of the present disclosure. Anembodiment of the full port hybrid CSI feedback scheme (Alt 0) 1800shown in FIG. 18 is for illustration only. One or more of the componentsillustrated in FIG. 18 can be implemented in specialized circuitryconfigured to perform the noted functions or one or more of thecomponents can be implemented by one or more processors executinginstructions to perform the noted functions. Other embodiments are usedwithout departing from the scope of the present disclosure. Anillustration of Alt 0 of the hybrid CSI feedback scheme is shown in FIG.18.

As shown in FIG. 18, the first CSI-RS corresponds to “Class A CSIreporting or eMIMO-Type” in which NP CSI-RS is transmitted from all2N₁N₂ ports (full-port), and the UE derives the CSI feedback comprising:the first PMI pair (i_(1,1), i_(1,2)) comprising of the second PMI i₂,(and CQI and RI) or the first PMI pair (i_(1,1), i_(1,2)) according tothe configured codebook such as Error! Reference source not found; andthe second CSI-RS corresponds to “Class B CSI reporting or eMIMO-Type”in which BF CSI-RS is transmitted from 2 ports which are beam-formedusing the beams associated with the first PMI of Class A CSI feedback,and the UE derives the single PMI i using Table (or second PMI i₂ usingError! Reference source not found.). Additionally, UE also derives CQIand RI.

Although the overhead of the BF or Class B CSI-RS transmission is small,that of the NP or Class A CSI-RS is still the same as before, i.e.,2N₁N2. To reduce overhead associated with the first (NP) CSI-RS, thepartial port NP CSI-RS is proposed in which CSI-RS is transmitted from asubset of 2N₁N₂ ports. In particular, the subset corresponds to one rowand one column of two-dimensional antenna port layout. Two alternatives(Alt 1 and Alt 2) of partial port NP CSI-RS are explained below.

FIG. 19 illustrates an example partial port hybrid CSI feedback scheme(Alt 1) 1900 according to embodiments of the present disclosure. Anembodiment of the partial port hybrid CSI feedback scheme (Alt 1) 1900shown in FIG. 19 is for illustration only. One or more of the componentsillustrated in FIG. 19 can be implemented in specialized circuitryconfigured to perform the noted functions or one or more of thecomponents can be implemented by one or more processors executinginstructions to perform the noted functions. Other embodiments are usedwithout departing from the scope of the present disclosure. Anillustration of Alt 1 of the proposed “partial port hybrid CSI feedbackscheme” is shown in FIG. 19.

In some embodiments, the first CSI-RS corresponds to “Class C CSIreporting or eMIMO-Type” in which NP CSI-RS is transmitted from a subsetof one row of antenna ports, and a subset of one column of antennaports. Four alternatives of such CSI-RS are also shown: Alt 1-1 requires2(N₁+N₂) CSI-RS, which are associated with all antenna ports in one row(both polarizations) and all antenna ports in one column (bothpolarizations); Alt 1-2 requires 2N₁+N₂ CSI-RS, which are associatedwith all antenna ports in one row (both polarizations, and all antennaports in one column with the same polarization, for example +45 degree;Alt 1-3 requires N₁+2N₂ CSI-RS, which are associated with all antennaports in one row with the same polarization, for example +45 degree andall antenna ports in one column (both polarizations); and Alt 1-4requires N₁+N₂ CSI-RS, which are associated with all antenna ports inone row with the same polarization, for example +45 degree and allantenna ports in one column with the same polarization, for example +45degree. In such embodiments, the UE is configured to derive i_(1,1) ofthe first PMI pair (i_(1,1), i_(1,2)) using the CSI-RS corresponding tothe row and i_(1,2) of the first PMI pair (i_(1,1), i_(1,2)) using theCSI-RS corresponding to the column. The UE may be configured with anappropriate DFT codebook to derive (i_(1,1), i_(1,2)). In thisalternative, the UE reports i_(1,1) and i_(1,2) jointly in the samereporting instance.

In some embodiments, the second CSI-RS corresponds to BF CSI-RS in whichCSI-RS is transmitted from 2 ports which are beam-formed using the beamsassociated with the first PMI, and the UE derives the single PMI i usingTable 18 (or second PMI i₂ using Table 20). Additionally, UE alsoderives CQI and RI. Two examples of this alternative (Alt 1-1 and Alt1-4) are also shown in FIG. 19.

FIG. 20 illustrates another example partial port hybrid CSI feedbackscheme (Alt 2) 2000 according to embodiments of the present disclosure.An embodiment of the partial port hybrid CSI feedback scheme (Alt 2)2000 shown in FIG. 20 is for illustration only. One or more of thecomponents illustrated in FIG. 20 can be implemented in specializedcircuitry configured to perform the noted functions or one or more ofthe components can be implemented by one or more processors executinginstructions to perform the noted functions. Other embodiments are usedwithout departing from the scope of the present disclosure.

An illustration of Alt 2 of the proposed “partial port hybrid CSIfeedback scheme” is shown in FIG. 20. In some embodiments, the firstCSI-RS corresponds to “Class C CSI reporting or eMIMO-Type” in which NPCSI-RS is transmitted from a subset of one row of antenna ports. In someembodiments, the second CSI-RS corresponds to “Class C CSI reporting oreMIMO-Type” in which NP CSI-RS is transmitted from a subset of onecolumn of antenna ports. In such embodiments, four alternatives of suchCSI-RS are also shown: Alt 2-1 requires 2N₁ CSI-RS which are associatedwith all antenna ports in one row (both polarizations); Alt 2-2 requiresN₁ CSI-RS, which are associated with all antenna ports in one row withthe same polarization, for example +45 degree; Alt 2-3 requires 2N₂CSI-RS, which are associated with all antenna ports in one column (bothpolarizations); and Alt 2-4 requires N₂ CSI-RS, which are associatedwith all antenna ports in one column with the same polarization, forexample +45 degree.

In such embodiments, the UE is configured to derive i_(1,1) of the firstPMI pair (i_(1,1), i_(1,2)) using the CSI-RS corresponding to the rowand i_(1,2) of the first PMI pair (i_(1,1), i_(1,2)) using the CSI-RScorresponding to the column. The UE may be configured with anappropriate DFT codebook to derive (i_(1,1), i_(1,2)). In thisalternative, the UE reports i_(1,1) and i_(1,2) jointly in the samereporting instance or separately in two different reporting instances.

In some embodiments, the third CSI-RS corresponds to BF CSI-RS in whichCSI-RS is transmitted from 2 ports which are beam-formed using the beamsassociated with the first PMI, and the UE derives the second PMI i₂using Error! Reference source not found. Additionally, UE also derivesCQI and RI. Two examples of this alternative (Alt 2-1 & Alt 2-3 and Alt2-2 & Alt 2-4) are also shown in FIG. 20.

Analyzing the first (NP) CSI-RS of the three alternatives, i.e., Alt 0,Alt 1, and Alt 2, we can observe: Alt 0 corresponds to a “2D full array”CSI-RS transmission since CSI-RS is transmitted from all 2N₁N₂ ports,and (i_(1,1), i_(1,2)) are derived jointly; Alt 1 and Alt 2 correspondto a “1D partial array” CSI-RS transmission since CSI-RS is transmittedfrom a row and a column (with both polarizations or +45 degreepolarization) of antenna ports, and i_(1,1) and i_(1,2) are derivedseparately; and For 1D antenna port layouts, Alt 0 is the same as Alt 1or Alt 2 in which both polarizations are configured for CSI-RStransmission. This also means that there is no CSI-RS overhead reductionin this case.

In some embodiments, the UE is configured with a “hybrid PMI codebook,”denoted as C_(H), which can be decomposed as a product of two PMIcodebooks, C_(NP) (associated with NP CSI-RS and Class C or AeMIMO-Type) and C_(BF) (associated with BF CSI-RS and Class B or AeMIMO-Type with K=1) depending on the eMIMO-Type configuration (seeTable 21).

There are at least two alternatives to represent the hybrid PMIpre-coder. In one embodiment of Alt 1, a hybrid PMI pre-coders p inC_(H) is represented as a product of: a first PMI pre-coder is P_(BD),which is a block diagonal matrix whose each diagonal block is p_(NP) inC_(NP) and a second PMI pre-coder is p_(BF) in C_(BF). That is,p=P_(BD)·p_(BF). In one embodiment of Alt 2, a hybrid PMI pre-coders pin C_(H) is represented as a Kronecker product of p_(BF) in C_(BF) andp_(NP) in C_(NP), i.e. p=p_(BF){circle around (x)}p_(NP) In oneembodiment of sub-alternatives of Alt 1, the diagonal blocks of the PMIpre-coder P_(BD) are the same (Alt 1-1). In one embodiments=ofsub-alternatives of Alt 1, the diagonal blocks of the PMI pre-coderP_(BD) can be different. In such embodiment, note that the hybrid PMIpre-coders in Alt 1-1 and in Alt 2 result in the same hybrid pre-coder.

FIG. 21 illustrates an example hybrid PMI pre-coder (Alt 1-1 and Alt 2)2100 according to embodiments of the present disclosure. An embodimentof the hybrid PMI pre-coder (Alt 1-1 and Alt 2) 2100 shown in FIG. 21 isfor illustration only. One or more of the components illustrated in FIG.21 can be implemented in specialized circuitry configured to perform thenoted functions or one or more of the components can be implemented byone or more processors executing instructions to perform the notedfunctions. Other embodiments are used without departing from the scopeof the present disclosure.

An illustration of the hybrid PMI pre-coder is shown in FIG. 21. For 1Dantenna ports, pre-coders p_(NP) and p_(BF) are vectors (hence 1D), andfor 2D antenna ports, they are either vectors (1D) or matrices (2D). Anshown, there are four identical “subarray” partitions of the entireantenna array, the same first PMI pre-coder p_(NP) is applied to bothpolarizations of the antenna ports within each subarray, which resultsin 2 beam-formed ports in each subarray. The same second PMI pre-coderp_(BF) is then applied to the two polarizations of the four subarrays.

In some embodiments, the configured codebooks C_(NP) and C_(BF)correspond to dual-polarized codebooks, i.e., the co-phase between twopolarizations is included in C_(NP) and C_(BF). In one example, thepre-coders p_(NP) and p_(BF) are expressed as:

${p_{NP} = {\begin{bmatrix}p_{NP}^{\prime} \\{\varphi_{{NP}^{\;}}p_{NP}^{\prime}}\end{bmatrix} \in C_{NP}}}\mspace{11mu}$  and${{p_{BF} = {\begin{bmatrix}p_{BF}^{\prime} \\{\varphi_{BF}p_{BF}^{\prime}}\end{bmatrix} \in C_{BF}}},}\;$

where p′_(NP) and p′_(BF) are DFT vectors of appropriate dimensions, andφ_(NP) and φ_(BF) are corresponding co-phase values.

In this case, the partial port NP first CSI-RS is transmitted fromantenna ports in the subarray with both polarizations, and BF secondCSI-RS is transmitted from the two beam-formed ports corresponding tothe two polarizations.

The pre-coders p′_(NP) and p′_(BF) are reported as two PMI pre-coders inClass C (or A) and Class B (or A) CSI reporting instances, respectively.

The two co-phase values are chosen from the respective co-phasecodebooks, C_(Co-ph,NP), and C_(Co-ph,BF), respectively. In one example,C_(Co-ph,NP)=C_(Co-ph,BF)={1, j, −1, −j}. So, 2-bits are needed toreport φ_(NP) and φ_(BF) in Class C (or A) and Class B (or A) CSIreporting instances, respectively. In another example,C_(Co-ph,NP)N={e^(jπ/4),e^(j3π/4),e^(j5π/4),e^(j7π/4)} andC_(Co-ph,BF)={e^(−jπ/4),e^(jπ/4)}. Note that in this case, for anyφ_(NP) in C_(Co-ph,NP) and θ_(BF) in C_(Co-ph,BF), we haveφ_(NP)φ_(BF)ε{1,j,−1,−j}. So, 2-bits and 1-bit respectively are neededto report φ_(NP) and φ_(BF) in Class C (or A) and Class B (or A) CSIreporting instances.

The UE may or may not be configured to report the co-phase φ_(NP). Insome embodiments, if the UE reports φ_(NP), then eNB appliesbeam-forming weights

$p_{NP} = \begin{bmatrix}p_{NP}^{\prime} \\{\varphi_{{NP}^{\;}}p_{NP}^{\prime}}\end{bmatrix}$

to antenna ports in each subarray (i.e., p′_(NP) to +45 polarization andφ_(NP)p′_(NP) to −45 polarization) and obtains two ports. The hybridpre-coder is then represented as

$p = {\begin{bmatrix}{p_{BF}^{\prime} \otimes p_{NP}^{\prime}} \\{\varphi_{BF}\varphi_{NP}{p_{BF}^{\prime} \otimes p_{NP}^{\prime}}}\end{bmatrix} \in {C_{H}.}}$

In some embodiments, if the UE does not report φ_(NP), then eNB appliesbeam-forming weights

$p_{NP} = \begin{bmatrix}p_{NP}^{\prime} \\p_{NP}^{\prime}\end{bmatrix}$

to antenna ports in each subarray (i.e., p′_(NP) to both +45 and −45polarization) and obtains two ports. The hybrid pre-coder is thenrepresented as

$p = {\begin{bmatrix}{p_{BF}^{\prime} \otimes p_{NP}^{\prime}} \\{\varphi_{BF}{p_{BF}^{\prime} \otimes p_{NP}^{\prime}}}\end{bmatrix} \in {C_{H}.}}$

In some embodiments, the configured C_(NP) corresponds to a co-polarizedcodebook (such as a DFT codebook), and C_(BF) corresponds todual-polarized codebooks. That is, the co-phase between twopolarizations is included in C_(BF), but not in C_(NP). In this case,eNB applies beam-forming weights

$p_{NP} = \begin{bmatrix}p_{NP}^{\prime} \\p_{NP}^{\prime}\end{bmatrix}$

to antenna ports in each subarray (i.e., p′_(NP) to both +45 and −45polarization) and obtains two ports, and hence the hybrid pre-coder isrepresented as

$p = {\begin{bmatrix}{p_{BF}^{\prime} \otimes p_{NP}^{\prime}} \\{\varphi_{BF}{p_{BF}^{\prime} \otimes p_{NP}^{\prime}}}\end{bmatrix} \in {C_{H}.}}$

In one example, partial port NP CSI-RS is transmitted from antenna portsin the subarray with one polarization only, for example +45 degree. Inanother method, it is transmitted from antenna ports in the subarraywith both polarizations. When CSI-RS is transmitted from bothpolarizations, the UE may optimize over the co-phase or use a defaultco-phase while deriving p_(NP).

In some embodiments, the configured C_(NP) corresponds to adual-polarized codebook, and C_(BF) corresponds to co-polarizedcodebooks (such as a DFT codebook). In this case, the co-phase φ_(NP) isreported in Class C (or A) CSI reporting instance according to someembodiments of the present disclosure, and no co-phase is reported inClass B (or A) CSI reporting instance. The hybrid pre-coder is thenrepresented as

$p = {{p_{BF} \otimes \begin{bmatrix}p_{NP}^{\prime} \\{\varphi_{NP}p_{NP}^{\prime}}\end{bmatrix}} \in {C_{H}.}}$

The eNB applies beam-forming weights

$p_{NP} = \begin{bmatrix}p_{NP}^{\prime} \\{\varphi_{NP}p_{NP}^{\prime}}\end{bmatrix}$

to antenna ports in each subarray (i.e., p′_(NP) to +45 polarization andφ_(Np)p′_(NP) to −45 polarization) and in Option 1 obtains a single portand in Option 2 obtains two ports. Note that the dimension of the p_(BF)vector is doubled in Option 2 when compared with Option 1.

In some embodiments, the UE is configured with the codebook C_(NP),which is an oversampled DFT codebook of appropriate dimension andoversampling factor. For instance, the codebook C_(NP) corresponds tothe Codebook-Config=1 in Table 20.

In some embodiments, C_(NP) and C_(BF) are configured to a UE implicitlyas one codebook C_(H). In some embodiments, C_(NP) and C_(BF) areconfigured to a UE explicitly as two codebooks. In some embodiments,C_(NP) and C_(BF) are legacy (up to LTE specification) PMI codebooks. Inanother alternative, one or both of them is non-legacy (up to LTEspecification) codebooks.

In some embodiments, one or both of C_(NP) and C_(BF) are doublecodebooks similar to Rel 13 FD-MIMO codebooks: C_(NP)=C_(NP1)C_(NP2) andC_(BF)=C_(BF1)C_(BF2), where C_(NP1) and C_(BF1) are WB and long-termfirst PMI codebooks, which may represent a beam (similar toCodebook-Config=1 in Rel 13 FD-MIMO codebooks) or a group of beams(similar to Codebook-Config=2, 3, 4 in LTE FD-MIMO codebooks); andC_(NP2) and C_(BF2): SB and short-term second PMI codebooks, which mayrepresent beam selection and co-phase.

It may be assumed that eMIMO-Type (CSI reporting type) is Class C forfirst NP CSI-RS resource, and it is Class B for second BF CSI-RSresource, unless otherwise stated. For brevity of notation, we will usethe subscripts “C” and “B” in place of “NP” and “BF” in codebook,pre-coder and co-phase notations, i.e., we will use C_(C) and C_(B) inplace of C_(NP) and C_(BF), p_(C) and p_(B) in place of p_(NP) andp_(BF), and φ_(C) and φ_(B) in place of φ_(NP) and φ_(BF). In general,the below embodiments are applicable to the case in which eMIMO-Type isClass C or A for first NP CSI-RS resource, and eMIMO-Type is Class B orA for second BF CSI-RS resource.

In some embodiments, the UE is configured with a “subarray based hybridCSI feedback scheme” in which the entire antenna array is partitionedinto identical subarrays of antenna ports, where a subarray is definedas a subset of antenna ports that are uniformly spaced. In suchembodiment, the antenna ports in a subarray are closely spaced. Forexample, the spacing between two nearest antenna ports in a subarray isequal to one. In such embodiment, they are widely spaced, for examplethe spacing between two nearest antenna ports in a subarray is more thanone. In such embodiments, the UE is configured with a “subarray basedhybrid CSI feedback scheme” in which the number of ports in the 1stdimension, denoted as M₁, of a subarray is at least one and at most N₁,and the number of ports in the 2nd dimension, denoted as M₂, is at leastone and at most N₂. In such embodiments, the UE is configured with a“subarray based hybrid CSI feedback scheme” in which a subarray is 1Dfor 1D antenna port layouts and is 1D or 2D for 2D antenna port layouts.

In some embodiments, the UE is configured with a “subarray based hybridCSI feedback scheme” in which there are two types of CSI-RS that areconfigured to a UE by the eNB. In such embodiments, the first (NP)CSI-RS corresponds to a subarray based “Class C eMIMO-Type” in whichCSI-RS is transmitted from one subarray of antenna ports, and the second(BF) CSI-RS corresponds to “Class B eMIMO-Type” in which CSI-RS istransmitted from 2 ports in each subarray which are beam-formed usingthe beam-forming weights obtained using the NP CSI-RS.

In some embodiments, the UE is configured with a “subarray based hybridCSI feedback scheme” in which the UE derives the Class C CSI reportwhich includes a first PMI i₁ for 1D and (i_(1,1),i_(1,2)) for 2D usingthe Class C CSI-RS from one subarray, where the first PMI represents thePMI pre-coder p_(C) in Class C codebook C_(C), and the Class B CSIreport which includes a second PMI i₂ corresponding to the PMI pre-coderp_(B) in the Class B codebook C_(B).

In some embodiments, the UE also reports CQI and RI. In one example, theUE reports CQI and RI in the Class B CSI reporting instance only. Inanother example, it reports CQI and RI in both Class C and Class B CSIreporting instances, where RI reported in Class C CSI report may be usedto configure a maximum value of RI reported in Class B CSI report. Inyet another method, it reports CQI in Class C and CQI and RI in Class Breporting instances, respectively.

In some embodiments, the UE reports the two PMIs, a first PMI and asecond PMI, in one or both of Class C and Class B reporting instances,where the first PMI is WB and long-term and the second PMI is SB andshort-term. For example, the UE may be configured to report the secondPMI in addition to the first PMI in Class C CSI reporting instance usingthe PMI codebook C_(C). The second PMI may correspond to the co-phasevalue for the two polarizations. The indicated co-phase value is usedtogether with the first PMI pre-coder p_(C) to beam-form Class B CSI-RStransmitted from multiple subarrays. Similarly, the UE may be configuredto report the first PMI in addition to the second PMI in Class B CSIreporting instance using the PMI codebook C_(B). The first PMI maycorrespond to the WB beam or beam group.

An example of eMIMO-Type or PMI reporting type configuration is shown inTable 21, where subscripts C and B are used to distinguish Class C andClass B reporting PMIs, respectively, and (i_(1C,1), i_(1C,2)), and(i_(1B,1), i_(1B,2)) correspond to a pair of 1st PMI for the twodimensions in case of 2D antenna ports, for Class C and Class B CSIreporting, respectively.

TABLE 21 eMIMO-Type or PMI reporting type configuration table CSIderived with the first (NP) CSI derived with the second (BF) CSI-RSresource CSI-RS resource CSI CSI reporting reporting class or class orConfig- eMIMO- eMIMO- uration Type 1st PMI 2nd PMI Type 1st PMI 2nd PMI0 C i_(1C) or — B — i_(2B) (i_(1C, 1), i_(1C, 2)) 1 A i_(1A) or i_(2A) B— i_(2B) (i_(1A, 1), i_(1A, 2)) 2 C i_(1C) or — A i_(1A) or i_(2A)(i_(1C, 1), i_(1C, 2)) (i_(1A, 1), i_(1A, 2)) 3 A i_(1A) or i_(2A) Ai_(1A) or i_(2A) (i_(1A, 1), i_(1A, 2)) (i_(1A, 1), i_(1A, 2))

In some embodiments, the UE is configured whether or not the co-phaseφ_(C) is reported in the Class C CSI reporting instance. In someembodiments, if the UE is configured to report the co-phase φ_(C), it isreported with the first PMI, i_(1C) (for 1D) or i_(1C,1) or i_(1C,2), or(i_(1C,1), i_(1C,2)) (for 2D). In this case, the first PMI correspondsto p′_(C) and φ_(C). In one example, the reported c is WB. In someembodiments, if the UE is configured to report the co-phase φ_(C), it isreported as a second PMI, i_(2C), in Class C CSI reporting instance. Inthis case, the first PMI corresponds to p′_(C) and the second PMIcorresponds to φ_(C). Here, the reported φ_(C) is either WB or SB.

FIG. 22 illustrates an example subarray based hybrid CSI feedback scheme2200 according to embodiments of the present disclosure. An embodimentof the subarray based hybrid CSI feedback scheme 2200 shown in FIG. 22is for illustration only. One or more of the components illustrated inFIG. 22 can be implemented in specialized circuitry configured toperform the noted functions or one or more of the components can beimplemented by one or more processors executing instructions to performthe noted functions. Other embodiments are used without departing fromthe scope of the present disclosure.

An illustration of the proposed subarray based hybrid CSI feedbackscheme is shown in FIG. 22. The entire antenna array is partitioned intofour subarrays, SA0, SA1, SA2, and SA3, each of which has a dimension of(M₁, M₂)=(4,1) in 1D example and (2,2) in 2D example. As shown (in red),the eNB transmits Class C CSI-RS from the subarray SA0. The UE derivesthe Class C CSI feedback including the 1st PMI pre-coder p_(C), andreports it to the eNB. eNB uses the 1st PMI pre-coder p_(C) to beam-formboth polarizations of the four subarrays and transmits 2-port Class BCSI-RS from each subarray or an aggregate of 8-port Class B CSI-RS fromentire antenna array. The UE then derives the Class B CSI feedbackincluding the 2nd PMI pre-coder p_(B) and feeds it back to eNB. The eNBderives the hybrid PMI pre-coder p using both p_(B) and p_(C), forexample, p=p_(B)

p_(C).

FIG. 23 illustrates an example subarray types 2300 according toembodiments of the present disclosure. An embodiment of the subarraytypes 2300 shown in FIG. 23 is for illustration only. One or more of thecomponents illustrated in FIG. 23 can be implemented in specializedcircuitry configured to perform the noted functions or one or more ofthe components can be implemented by one or more processors executinginstructions to perform the noted functions. Other embodiments are usedwithout departing from the scope of the present disclosure.

Examples of several subarray partitions are shown in FIG. 23. As shownat the top of the figure, there are N_(p)=2N₁N₂ antenna ports in totaland several types of subarray constructions are shown. For instance, inEx 1 (left column), N_(p)/2 antenna ports form a subarray, and in Ex 2(right column), N_(p)/4 antenna ports form a subarray. In Co-pol (toprow), the Class C (or partial NP) antenna ports that form a subarrayhave +45 degree polarization, and in X-pol (bottom row), the Class C (orpartial NP) antenna ports that form a subarray have both polarizations.Ex 1-1 to Ex 1-3 and Ex 2-1-Ex 2-5 correspond to the subarrays in whichthe spacing between two nearest ports in the subarray is 1, and Ex 1-4to Ex 1-5 and Ex 2-6 to Ex 2-10 correspond to the subarrays in which thespacing between two nearest ports in the subarray is 2 (more than 1).

Depending on the Class C PMI pre-coder p_(C), the Class B PMI pre-codermay have the following components: co-phase for the two polarizations(the x-pol co-phase is an essential component of the Class B PMIpre-coder); and pre-coder component in dimension d (If M_(d)<N_(d), thenthe pre-coder component in dimension d is a vector of length

$\lceil \frac{N_{d}}{M_{d}} \rceil {\text{)}.}$

Table 24 shows the components of Class B PMI pre-coder for the examplesas shown in FIG. 23.

TABLE 24 Class B PMI pre-coder components Class B pre-coder (p_(B))components Co- Pre-coder Pre-coder Ex phase in 1st dim in 2nd dim 1.1Yes No No 1.2, 1.4, 2.1, 2.3, 2.6 Yes Yes No 1.3, 1.5, 2.2, 2.4, 2.7 YesNo Yes 2.5, 2.8, 2.9, 2.10 Yes Yes Yes

In some embodiments, a UE is configured with one CSI process with twotypes of NZP CSI-RS resources: 1st CSI-RS resource is either NP CSI-RSor BF CSI-RS with K₁>1 resource; and 2nd CSI-RS resource is either BFCSI-RS with K₂=1 resource or BF CSI-RS with K₂=1 resources. The two NZPCSI-RS resources are associated with two eMIMO-Types according to theconfiguration where supported eMIMO-Type combinations are according toTable 25.

TABLE 25 Supported eMIMO-Type combinations for hybrid CSI reporting CSIderived with the CSI derived with the second first (NP) CSI-RS resource(BF) CSI-RS resource eMIMO- CSI eMIMO- CSI Configuration Type reportingcontent Type reporting content 0 Class A i₁ or (i_(1,1), i_(1,2)), RIClass B K₂ = 1 RI, CQI, PMI i₂ 1 Class A i₁ or (i_(1,1), i_(1,2)), RIClass B K₂ = 1 CQI, PMI i₂ 2 Class A i₁ or (i_(1,1), i_(1,2)) Class B K₂= 1 RI, CQI, PMI i₂ 3 Class B CRI Class B K₂ = 1 RI, CQI, PMI i₂ K₁ > 14 Class B K₁ independent CSI reports Class B K₂ = 1 RI, CQI, PMI i₂ K₁ >1 each includes at least a PMI 5 Class A i₁ or (i_(1,1), i_(1,2)), RIClass B CRI, and {RI, CQI, K₂ > 1 PMI i₂} conditioned on CRI

FIG. 24 illustrates an example subarray cycling at an eNB 2400 accordingto embodiments of the present disclosure. An embodiment of the subarraycycling at an eNB 2400 shown in FIG. 24 is for illustration only. One ormore of the components illustrated in FIG. 24 can be implemented inspecialized circuitry configured to perform the noted functions or oneor more of the components can be implemented by one or more processorsexecuting instructions to perform the noted functions. Other embodimentsare used without departing from the scope of the present disclosure.

In some embodiments, eNB cycles through all subarrays to transmit ClassC CSI-RS. An example of subarray cycling is shown in FIG. 24. At t0, eNBtransmits Class C CSI-RS using subarray SA0 and UE feeds back thepre-coder p_(C), and eNB uses it to beam-form Class C CSI-RS. At t1, eNBtransmits Class C CSI-RS using subarray SA1 and UE feeds back p_(C), andthe same is repeated for subarrays SA2 and SA3. After that, the subarraycycling process continues in the sequence SA0, SA1, SA2, and SA3.

In one embodiment, the reported pre-coder p_(C) is used to beam-formClass B CSI-RS transmitted through all subarrays. In this method, thepre-coder p_(C) is the same for all subarrays, hence the hybridpre-coder has the structure:

$p = {\begin{bmatrix}p_{c} & 0 & \ldots & 0 \\0 & p_{c} & \ldots & 0 \\\vdots & \vdots & \ddots & \ddots \\0 & 0 & \ldots & p_{c}\end{bmatrix}{p_{B}.}}$

In one embodiment, the reported pre-coder p_(C) is used to beam-formClass B CSI-RS transmitted through the corresponding subarray. The ClassB CSI-RS transmitted through the rest of the subarrays are beam-formedusing their respective pre-coders p_(C) that are most recently reported.In this method, the pre-coder p_(C) may be different for all subarrays,hence the hybrid pre-coder has the structure:

${p = {\begin{bmatrix}p_{c,0} & 0 & \ldots & 0 \\0 & p_{c,1} & \ldots & 0 \\\vdots & \vdots & \ddots & \ddots \\0 & 0 & \ldots & p_{c,{Q - 1}}\end{bmatrix}p_{B}}},$

where p_(C,q) denotes the pre-coder at subarray qε{0, 1, . . . , Q−1},where Q is the number of subarrays. Note Q=Q₁Q₂ for 2D antenna ports.

To initialize, all subarrays may be initialized with the same pre-coderp_(C) which may be obtained in the first Class C CSI reporting instance,or using UL SRS measurement (assuming UL-DL channel reciprocity).

In some embodiments, eNB partitions the entire subarray into K subarraysand transmits NZP CSI-RS from each of K subarrays where CSI-RS caneither be NP or BF. Also, K CSI-RS resources may belong to a single CSIprocess of K independent processes. Using these K resources in the 1ststage, the UE derives the 1st stage pre-coder for each subarray whichare in turn used to beam-form 2nd stage BF CSI-RS according to someembodiments of the present disclosure.

In some embodiments, the UE is configured with a subarray type from aplurality of subarray types such that they correspond to the supportedantenna port configurations (up to LTE specification) in terms of (N₁,N₂) values. In some embodiments, the UE is configured with a subarraytype from a plurality of subarray types such that at least one of themdo not correspond to the supported antenna port configurations (up toLTE specification) in terms of (N1, N₂) values. In some embodiments, theUE is configured with a subarray type configuration in terms of (N₁, N₂)for the full antenna port layout and (M₁, M₂) for the Class C subarrayport layout.

In some embodiments, the UE is configured with a subarray typeconfiguration in terms of (N₁, N₂) for the full antenna port layout and(Q₁, Q₂) for the Class B port layout after they beam-formed using theClass C PMI pre-coder. In some embodiments, the UE is configured with asubarray type configuration in terms of (M₁, M₂) for the Class Csubarray port layout and (Q₁, Q₂) for the Class B port layout after theybeam-formed using the Class C PMI pre-coder. In some embodiments,N₁=M₁Q₁ and N₂=M₂Q₂. In some embodiments, the subarray typeconfiguration is cell-specific, and hence remains the same for all UEs.In some embodiments, the subarray type configuration is UE-specific, andhence a UE is configured with a subarray type from a plurality ofsubarray types. In some embodiments, the UE suggests a preferredsubarray type to the eNB. In some embodiments, the subarray type ispre-determined, hence does not need configuration. In some embodiments,the subarray type configuration is semi-static via RRC or is moredynamic via CSI configuration.

In some embodiments, the codebook type configuration includes some ofthe following parameters: subarray type configuration to configure thesubarray type according to some embodiments of the present disclosure;(s₁, s₂) the spacing between two nearest antenna ports in the subarray.The set of values for s₁ and s₂ includes 1; (O_(1C), O_(2C)), theoversampling factors for Class C codebook C_(C); (O_(1B), O_(2B)), theoversampling factors for Class B codebook C_(B); andcodebook-configuration, the set of values include 1, 2, 3, 4 which mayor may not correspond to LTE specification FD-MIMO codebook.

In some embodiments, if the UE is configured with Class A eMIMO-Type in1st or 2nd CSI report, then the Codebook-Config parameter can beaccording to the following alternatives: Alt 0 (it is pre-determined),Ex 0 (Codebook-Config=1); and Alt 1 (codebook-Config value isconfigured) with codebook-Config=1, 2 for 1D port layouts, andcodebook-Config=1, 2, 3, 4 for 2D port layouts.

In some embodiments, if the UE is configured with Class A eMIMO-Type inboth CSI reports, then the Codebook-Config parameter can be according tothe following alternatives: Alt 0 (it is pre-determined), Ex 0:Codebook-Config=1 for both CSI reports and Ex 1: Codebook-Config=1 for1st CSI report, and Codebook-Config=2 if the 2nd CSI report isassociated with 2D beam-formed ports and Codebook-Config=4 the 2nd CSIreport is associated with 1D beam-formed ports; Alt 1 (oneCodebook-Config value is configured for both CSI reports),codebook-Config=1, 2 for 1D port layouts, and codebook-Config=1, 2, 3, 4for 2D port layouts; and Alt 2: Codebook-Config1 and Codebook-Config2are configured for both CSI reports, codebook-Config1,Codebook-Config2=1,2 for 1D port layouts, and codebook-Config1,Codebook-Config2=1, 2, 3, 4 for 2D port layouts.

In some embodiments, the Class C and Class B CSI-RS configuration andreporting can any of the following types: both are periodic with thesame periodicity; both are periodic with different periodicity, forexample Class C has longer periodicity; both are aperiodic; Class C isperiodic and Class B is aperiodic; and Class C is aperiodic and Class Bis periodic.

In some embodiments, eNB uses the hybrid PMI codebook and the associatedsubarray based hybrid CSI feedback framework to configure one of thefollowing: partial port hybrid (Class C+Class B) CSI feedback, forexample, M₁<N₁ or/and M₂<N₂, and both Class A and Class B CSI-RS areconfigured; full port hybrid (Class A+Class B) CSI feedback, forexample, M₁=N₁ and M₂=N₂, and both Class C and Class B CSI-RS areconfigured; Class A CSI feedback, for example: M₁=N₁ and M₂=N₂, p_(B)=1,and only Class A CSI-RS is configured; and Class B CSI feedback, forexample, only Class B CSI-RS is configured and p_(C) is replaced with anappropriate beam-forming vector, which for example is estimated using ULSRS assuming UL-DL (long-term) channel reciprocity. An example offeedback type configuration table is shown in Table 26.

TABLE 26 Feedback type configuration table NP CSI-RS BF CSI-RS DimensionPre-coder Dimension Pre-coder Full port hybrid (N₁, N₂) p_(A) (<N₁, <N₂)p_(B) Partial port hybrid (M₁, M₂) p_(C) (N₁/M₁, N₂/M₂) p_(B) Class A(N₁, N₂) p_(A) — 1 Class B — — (<N₁, <N₂) p_(B)

FIG. 25 illustrates an example millimeter wave communication system withhybrid beam forming (HBF) 2500 according to embodiments of the presentdisclosure. An embodiment of the millimeter wave communication systemwith HBF 2500 shown in FIG. 25 is for illustration only. One or more ofthe components illustrated in FIG. 25 can be implemented in specializedcircuitry configured to perform the noted functions or one or more ofthe components can be implemented by one or more processors executinginstructions to perform the noted functions. Other embodiments are usedwithout departing from the scope of the present disclosure.

In some embodiments, eNB uses the proposed hybrid CSI feedback frameworkfor a millimeter wave communication system with hybrid beam-formingarchitecture as shown in FIG. 25. In this architecture, there are N_(t)RF chains. Each RF chain consists of N_(t) ^(RF) antennae, where eachantenna is connected to one RF phase shifter. The phase values of thephase shifters of the i^(th) RF chain form a N_(t) ^(RF)×1 beam-formingvector w_(i). All RF chains together form a N_(t)×N_(t) block diagonalbeam-forming matrix W whose each diagonal block is a N_(t) ^(RF)×1beam-forming vector. Each RF chain receives an input from a N_(t)×N_(s)digital pre-coder matrix P, which maps N_(s) data streams to N_(t) RFchains.

FIG. 26 illustrates an example hybrid CSI feedback framework formillimeter wave communication system 2600 according to embodiments ofthe present disclosure. An embodiment of the hybrid CSI feedbackframework for millimeter wave communication system 2600 shown in FIG. 26is for illustration only. One or more of the components illustrated inFIG. 26 can be implemented in specialized circuitry configured toperform the noted functions or one or more of the components can beimplemented by one or more processors executing instructions to performthe noted functions. Other embodiments are used without departing fromthe scope of the present disclosure.

Assuming RF beam-forming matrix W has the identical diagonal blocks,which are selected from a RF beam codebook C_(RF) consisting of R RFbeams, eNB transmits Class C CSI-RS as BRS (beam RS) from one RF chainthrough all R RF beams in C_(RF) one-by-one, and UE derives the best RFbeam based on a metric. This beam scanning is performed at thegranularity of one OFDM symbol. In one OFDM symbol, WB measurement ofone RF beam is obtained. So, to obtain measurements through all RF beamsin C_(RF), R OFDM symbols are used. The best RF beam thus obtained isused as an RF beam-forming weight at all RF chains, and then Class BCSI-RS is transmitted through all N_(t) RF chains. An illustration ofthe hybrid CSI feedback for millimeter wave communication system isshown FIG. 26.

The Class C CSI feedback includes the first PMI indicating the selectedRF beam from C_(RF). In one example, C_(RF) is a DFT codebook where thelength of each DFT vector is N_(t) ^(RF). The Class B CSI feedbackincludes the second PMI indicating the digital pre-coder, CQI, and RIaccording to some embodiments of the present disclosure.

In some embodiments, eNB, instead of using the same RF beam at all RFchains, performs subarray cycling for Class C CSI-RS transmissionaccording to some embodiments of the present disclosure, and updates RFbeams at all subarrays one-by-one.

FIG. 27 illustrates an example UE-transparent eNB and UE procedures 2700according to embodiments of the present disclosure. An embodiment of theUE-transparent eNB and UE procedures 2700 shown in FIG. 27 is forillustration only. One or more of the components illustrated in FIG. 27can be implemented in specialized circuitry configured to perform thenoted functions or one or more of the components can be implemented byone or more processors executing instructions to perform the notedfunctions. Other embodiments are used without departing from the scopeof the present disclosure.

In some embodiments, as shown in FIG. 27, a UE is configured to: measuretwo CSI-RSs associated with Class C and Class B eMIMO-Types; derive twoPMIs using respective PMI codebooks (C_(C) and C_(B)); and report themin the two respective PMI reporting instances. The UE also derives andreports CQI and RI in one or both CSI reporting types according to theconfiguration.

eNB aggregates the reported Class C and Class B CSIs and derives thehybrid CSI comprising of: the hybrid pre-coder p_(H) using the tworeported PMIs p_(C) and p_(B) according to some embodiments of thepresent disclosure; the overall CQI if CQI is reported in CQI reportinginstances of both Class C and Class B CSIs; and the overall RI if RI isreported in RI reporting instances of both Class C and Class B CSIs. Inthis case, the UE is unaware of the hybrid PMI codebook that eNB uses toderive hybrid CSI.

FIG. 28 illustrates an example UE-non-transparent eNB and UE procedures(Alt 0) 2800 according to embodiments of the present disclosure. Anembodiment of the UE-non-transparent eNB and UE procedures (Alt 0) 2800shown in FIG. 28 is for illustration only. One or more of the componentsillustrated in FIG. 28 can be implemented in specialized circuitryconfigured to perform the noted functions or one or more of thecomponents can be implemented by one or more processors executinginstructions to perform the noted functions. Other embodiments are usedwithout departing from the scope of the present disclosure.

In some embodiments, as shown in FIG. 28, a UE is configured to: measuretwo CSI-RSs associated with Class C and Class B eMIMO-Types; derive twoPMIs using respective PMI codebooks (C_(C) and C_(B)) with the knowledgeabout the hybrid PMI codebook which eNB will use to derive the hybridCSI, and report them in the two respective PMI reporting instances. TheUE also derives and reports CQI and RI in one or both CSI reportingtypes according to the configuration. The eNB aggregates the reportedClass C and Class B CSIs and derives the hybrid CSI comprising of: thehybrid pre-coder p_(H) using the two reported PMIs p_(C) and p_(B)according to some embodiments of the present disclosure; the overall CQIif CQI is reported in CQI reporting instances of both Class C and ClassB CSIs; and the overall RI if RI is reported in RI reporting instancesof both Class C and Class B CSIs.

The UE uses one of the following exemplary implementations to use thehybrid PMI codebook information: implementation 0 (information about thehybrid pre-coder is used only in Class C CSI derivation as shown in FIG.28); implementation 1 (information about the hybrid pre-coder is usedonly in Class B CSI derivation as shown in FIG. 28; and implementation 2(information about the hybrid pre-coder is used in both Class C andClass B CSI derivations as shown in FIG. 28.

For each implementation, the UE uses one of the following exemplarymethods: method 0 (the UE uses the last reported Class B CSI to deriveClass C CSI and vice versa); method 1 (the UE performs exhaustive searchover all pre-coders p_(B) in C_(B) to derive Class C CSI and viceversa); method 2 (the UE performs partial search over a subset ofpre-coders p_(B) in C_(B) to derive Class C CSI and vice versa); andmethod 4 (the UE obtains an “optimal” p_(B) in Ca analytically (withoutcodebook search) and use it to derive Class C CSI and vice versa).

FIG. 29 illustrates another example UE-non-transparent eNB and UEprocedures (Alt 1) 2900 according to embodiments of the presentdisclosure. An embodiment of the UE-non-transparent eNB and UEprocedures (Alt 1) 2900 shown in FIG. 29 is for illustration only. Oneor more of the components illustrated in FIG. 29 can be implemented inspecialized circuitry configured to perform the noted functions or oneor more of the components can be implemented by one or more processorsexecuting instructions to perform the noted functions. Other embodimentsare used without departing from the scope of the present disclosure.

In some embodiments, as shown in FIG. 29, a UE is configured to: measuretwo CSI-RSs associated with Class C and Class B eMIMO-Types; deriveClass C PMI using the PMI codebook C_(C) (with Implementation 1 or 2);derive hybrid PMI (or Class B PMI) using the hybrid PMI codebook C_(H)(or C_(B)) and the last reported Class C PMI, and report the two PMIs inthe two respective PMI reporting instances. The UE also derives andreports Class C CQI and RI and hybrid CQI and RI according to theconfiguration. Note that in this case, eNB does not need to aggregateClass C and Class B CSIs to obtain hybrid CSI as in the previousembodiment (Alt 0).

FIG. 30 illustrates yet another example UE-non-transparent eNB and UEprocedures (Alt 2) 3000 according to embodiments of the presentdisclosure. An embodiment of the UE-non-transparent eNB and UEprocedures (Alt 2) 3000 shown in FIG. 30 is for illustration only. Oneor more of the components illustrated in FIG. 30 can be implemented inspecialized circuitry configured to perform the noted functions or oneor more of the components can be implemented by one or more processorsexecuting instructions to perform the noted functions. Other embodimentsare used without departing from the scope of the present disclosure.

In some embodiments, as shown in FIG. 30, a UE is configured to: measuretwo CSI-RSs associated with Class C and Class B eMIMO-Types; derive 1sthybrid PMI (or Class C PMI) using the hybrid PMI codebook C_(H) (orC_(C)) and the last reported Class B PMI; derive 2nd hybrid PMI (orClass B PMI) using the hybrid PMI codebook C_(H) (or C_(B)) and the lastreported Class C PMI; and report the two hybrid PMIs in the tworespective PMI reporting instances. The UE also derives and reportshybrid CQI and RI in one or both CSI reporting according to theconfiguration.

In some embodiments, a UE is configured with a CSI process with threeNZP CSI-RS resources and three eMIMO-Types where: 1st CSI-RS (NP or BF)with K₁ resources is transmitted from K₁ subarrays according to someembodiments of the present disclosure; 2nd CSI-RS (BF) with K₂ resourcesis transmitted in the 2nd stage where CSI-RS is beam-formed using thePMI reported in 1st stage, here either K₂=1 or K₂>1; and 3rd CSI-RS (BF)with a single NZP resources associated with 2 ports (for the twopolarizations).

The three eMIMO-Types are configured as follows: 1st eMIMO-Type isassociated with 1st CSI-RS and is used to report beamforming (1st PMI)for the 2nd and 3rd CSI-RS; 2nd eMIMO-Type is associated with 2nd CSI-RSand is used to report beamforming (2nd PMI) for the 3rd stage (togetherwith 1st PMI); 3rd eMIMO-Type is associated with 3rd CSI-RS and is usedto report a co-phase (3rd PMI) and CQI. The periodicity of 1steMIMO-Type is the longest (i.e. 100 ms), that of the 2nd eMIMO-Type isintermediate (i.e. 50 ms), and that of the 3rd eMIMO-Type is everyPMI/CQI reporting instances, i.e. 5 ms.

In one alternative, RI is reported only in the 3rd stage. In anotheralternative, RI is reported in all three stages where 1st stage RI1 maysuggest preferred RIs for 2nd and 3rd stages.

In some embodiments, a UE is configured the 1st stage eMIMO-Type ofClass A or Class C to report the number of beams (L) in addition to it,RI, or CRI. The reported number of beams can be used to suggest apreferred RI value (or range of RI values) to eNB. In one method, L canbe reported based on Codebook-Config parameter as follows: ifCodebook-Config=1, then (a) L=1 beam indicates rank 1-2. So, RI in stage2 is 1-2, (b) L=2 beams (orthogonal) indicate rank 3-4. So, RI in stage2 is 3-4 or 1-4, (c) L=3 beams (orthogonal) indicate rank 5-6. So, RI instage 2 is 5-6 or 1-6m, and (d) L=4 beams (orthogonal) indicate rank7-8. So, RI in stage 2 is 7-8 or 1-8; and if Codebook-Config=2, 3, 4,then (a) L=4 beams indicates rank 1-2. So, RI in stage 2 is 1-2, (b) L=8beams (4 orthogonal pairs) indicate rank 3-4. So, RI in stage 2 is 3-4or 1-4, (c) L=3 beams (orthogonal) indicate rank 5-6. So, RI in stage 2is 5-6 or 1-6, and (d) L=4 beams (orthogonal) indicate rank 7-8. So, RIin stage 2 is 7-8 or 1-8.

In some embodiments (Set 1), when a UE is configured with 1^(st)eMIMO-Type of Class A and 2^(nd) eMIMO-Type of Class B with K=1resource, where the CSI reporting content for the 1^(st) eMIMO-Type(Class A) is i₁ ⁽¹⁾ or (i_(1,1) ⁽¹⁾, i_(1,2) ⁽¹⁾) and x-bit RI⁽¹⁾ (i.e.,CQI⁽¹⁾ and i2⁽¹⁾ are not reported), where if UE supports up to 2 layers,x=0, and if UE supports up to 8 layer, x=1, where RI⁽ ⁾={1, 3}; and the2^(nd) eMIMO-Type (Class B K=1) is CQI⁽²⁾, PMI⁽²⁾, RI⁽²⁾, wheresuperscript (y) represents the y-th eMIMO-Type, where y=1, 2, the UE isconfigured with periodic CSI reporting of 1^(st) and 2^(nd) eMIMO-Typesaccording to one of the following alternatives.

Using the PUCCH formats, any of the following combinations of UCItransmission rule on PUCCH can be supported, whether by itself or inaddition to other combinations. Such a combination can also include onlyone of the rules (set 1) below: Format 2 for a first CSI report(associated with a 1st eMIMO-Type of Class A) when not multiplexed withHARQ-ACK and Format 2 for a second CSI report (associated with a 2ndeMIMO-Type of Class B with one CSI-RS resource) when not multiplexedwith HARQ-ACK; Format 2 for a first CSI report (associated with a 1steMIMO-Type of Class A) when not multiplexed with HARQ-ACK and Format 3for a second CSI report (associated with a 2nd eMIMO-Type of Class Bwith one CSI-RS resource) when not multiplexed with HARQ-ACK; Format 3for a first CSI report (associated with a 1st eMIMO-Type of Class A)when not multiplexed with HARQ-ACK and Format 2 for a second CSI report(associated with a 2nd eMIMO-Type of Class B with one CSI-RS resource)when not multiplexed with HARQ-ACK; Format 3 for a first CSI report(associated with a 1st eMIMO-Type of Class A) when not multiplexed withHARQ-ACK and Format 3 for a second CSI report (associated with a 2ndeMIMO-Type of Class B with one CSI-RS resource) when not multiplexedwith HARQ-ACK; Format 2a for a first CSI report (associated with a 1steMIMO-Type of Class A) multiplexed with 1-bit HARQ-ACK for normal cyclicprefix and Format 2a for a second CSI report (associated with a 2ndeMIMO-Type of Class B with one CSI-RS resource) multiplexed with 1-bitHARQ-ACK for normal cyclic prefix; Format 2a for a first CSI report(associated with a 1st eMIMO-Type of Class A) multiplexed with 1-bitHARQ-ACK for normal cyclic prefix and Format 3 for a second CSI report(associated with a 2nd eMIMO-Type of Class B with one CSI-RS resource)when not multiplexed with HARQ-ACK; Format 2a for a first CSI report(associated with a 1st eMIMO-Type of Class A) multiplexed with 1-bitHARQ-ACK for normal cyclic prefix and Format 3a for a second CSI report(associated with a 2nd eMIMO-Type of Class B with one CSI-RS resource)multiplexed with 1-bit HARQ-ACK for normal cyclic prefix; Format 2a fora first CSI report (associated with a 1st eMIMO-Type of Class A)multiplexed with 1-bit HARQ-ACK for normal cyclic prefix and Format 3for a second CSI report (associated with a 2nd eMIMO-Type of Class Bwith one CSI-RS resource) multiplexed with 1-bit HARQ-ACK for normalcyclic prefix; Format 3 for a first CSI report (associated with a 1steMIMO-Type of Class A) when not multiplexed with HARQ-ACK and Format 2afor a second CSI report (associated with a 2nd eMIMO-Type of Class Bwith one CSI-RS resource) multiplexed with 1-bit HARQ-ACK for normalcyclic prefix; Format 3a for a first CSI report (associated with a 1steMIMO-Type of Class A) multiplexed with 1-bit HARQ-ACK for normal cyclicprefix and Format 2a for a second CSI report (associated with a 2ndeMIMO-Type of Class B with one CSI-RS resource) multiplexed with 1-bitHARQ-ACK for normal cyclic prefix; Format 3 for a first CSI report(associated with a 1st eMIMO-Type of Class A) multiplexed with 1-bitHARQ-ACK for normal cyclic prefix and Format 2a for a second CSI report(associated with a 2nd eMIMO-Type of Class B with one CSI-RS resource)multiplexed with 1-bit HARQ-ACK for normal cyclic prefix; Format 3a fora first CSI report (associated with a 1st eMIMO-Type of Class A)multiplexed with 1-bit HARQ-ACK for normal cyclic prefix and Format 3afor a second CSI report (associated with a 2nd eMIMO-Type of Class Bwith one CSI-RS resource) multiplexed with 1-bit HARQ-ACK for normalcyclic prefix; Format 3 for a first CSI report (associated with a 1steMIMO-Type of Class A) multiplexed with 1-bit HARQ-ACK for normal cyclicprefix and Format 3 for a second CSI report (associated with a 2ndeMIMO-Type of Class B with one CSI-RS resource) multiplexed with 1-bitHARQ-ACK for normal cyclic prefix; Format 2b for a first CSI report(associated with a 1 st eMIMO-Type of Class A) multiplexed with 2-bitHARQ-ACK for normal cyclic prefix and Format 2b for a second CSI report(associated with a 2nd eMIMO-Type of Class B with one CSI-RS resource)multiplexed with 2-bit HARQ-ACK for normal cyclic prefix; Format 2b fora first CSI report (associated with a 1st eMIMO-Type of Class A)multiplexed with 2-bit HARQ-ACK for normal cyclic prefix and Format 3for a second CSI report (associated with a 2nd eMIMO-Type of Class Bwith one CSI-RS resource) when not multiplexed with HARQ-ACK; Format 2bfor a first CSI report (associated with a 1st eMIMO-Type of Class A)multiplexed with 2-bit HARQ-ACK for normal cyclic prefix and Format 3bfor a second CSI report (associated with a 2nd eMIMO-Type of Class Bwith one CSI-RS resource) multiplexed with 2-bit HARQ-ACK for normalcyclic prefix; Format 2b for a first CSI report (associated with a 1steMIMO-Type of Class A) multiplexed with 2-bit HARQ-ACK for normal cyclicprefix and Format 3 for a second CSI report (associated with a 2ndeMIMO-Type of Class B with one CSI-RS resource) multiplexed with 2-bitHARQ-ACK for normal cyclic prefix; Format 3 for a first CSI report(associated with a 1st eMIMO-Type of Class A) when not multiplexed withHARQ-ACK and Format 2b for a second CSI report (associated with a 2ndeMIMO-Type of Class B with one CSI-RS resource) multiplexed with 2-bitHARQ-ACK for normal cyclic prefix; Format 3b for a first CSI report(associated with a 1st eMIMO-Type of Class A) multiplexed with 2-bitHARQ-ACK for normal cyclic prefix and Format 2b for a second CSI report(associated with a 2nd eMIMO-Type of Class B with one CSI-RS resource)multiplexed with 2-bit HARQ-ACK for normal cyclic prefix; Format 3 for afirst CSI report (associated with a 1st eMIMO-Type of Class A)multiplexed with 2-bit HARQ-ACK for normal cyclic prefix and Format 2bfor a second CSI report (associated with a 2nd eMIMO-Type of Class Bwith one CSI-RS resource) multiplexed with 2-bit HARQ-ACK for normalcyclic prefix; Format 3b for a first CSI report (associated with a 1steMIMO-Type of Class A) multiplexed with 2-bit HARQ-ACK for normal cyclicprefix and Format 3b for a second CSI report (associated with a 2ndeMIMO-Type of Class B with one CSI-RS resource) multiplexed with 2-bitHARQ-ACK for normal cyclic prefix; Format 3 for a first CSI report(associated with a 1 st eMIMO-Type of Class A) multiplexed with 2-bitHARQ-ACK for normal cyclic prefix and Format 3 for a second CSI report(associated with a 2nd eMIMO-Type of Class B with one CSI-RS resource)multiplexed with 2-bit HARQ-ACK for normal cyclic prefix; Format 2 for afirst CSI report (associated with a 1st eMIMO-Type of Class A) withHARQ-ACK for extended cyclic prefix and Format 2 for a second CSI report(associated with a 2nd eMIMO-Type of Class B with one CSI-RS resource)with HARQ-ACK for extended cyclic prefix; Format 2 for a first CSIreport (associated with a 1st eMIMO-Type of Class A) with HARQ-ACK forextended cyclic prefix and Format 3 for a second CSI report (associatedwith a 2nd eMIMO-Type of Class B with one CSI-RS resource) with HARQ-ACKfor extended cyclic prefix; Format 3 for a first CSI report (associatedwith a 1st eMIMO-Type of Class A) with HARQ-ACK for extended cyclicprefix and Format 2 for a second CSI report (associated with a 2ndeMIMO-Type of Class B with one CSI-RS resource) with HARQ-ACK forextended cyclic prefix; Format 3 for a first CSI report (associated witha 1st eMIMO-Type of Class A) with HARQ-ACK for extended cyclic prefixand Format 3 for a second CSI report (associated with a 2nd eMIMO-Typeof Class B with one CSI-RS resource) with HARQ-ACK for extended cyclicprefix.

The aforementioned transmission rules, the a new PUCCH Format 3a/3b forsimultaneous transmission of CSI and HARQ ACK/NACK can be defined asshown in FIG. 31.

FIG. 31 illustrates an example physical uplink control channel (PUCCH)Format 3a/3b for simultaneous CSI and hybrid automatic repeat request(HARQ) acknowledgement/negative acknowledgement (ACK/NACK) transmissionaccording to embodiments of the present disclosure. An embodiment of thePUCCH Format 3a/3b for simultaneous CSI and HARQ ACK/NACK transmission3100 shown in FIG. 31 is for illustration only. One or more of thecomponents illustrated in FIG. 31 can be implemented in specializedcircuitry configured to perform the noted functions or one or more ofthe components can be implemented by one or more processors executinginstructions to perform the noted functions. Other embodiments are usedwithout departing from the scope of the present disclosure.

In some embodiments (Set 2), any of the following combinations of UCItransmission rule on PUCCH can also be supported, whether by itself orin addition to other combinations. Such a combination can also includeonly one of the rules below. This combination can also be supported inconjunction with any combination from the preceding set of embodiments(Set 1): Format 3 for a first and a second CSI reports (associatedrespectively with a 1st eMIMO-Type of Class A and a 2nd eMIMO-Type ofClass B with one CSI-RS resource) when not multiplexed with HARQ-ACK;Format 3 for a first and a second CSI reports (associated respectivelywith a 1st eMIMO-Type of Class A and a 2nd eMIMO-Type of Class B withone CSI-RS resource) multiplexed with 1-bit HARQ-ACK for normal cyclicprefix; Format 3 for a first and a second CSI reports (associatedrespectively with a 1st eMIMO-Type of Class A and a 2nd eMIMO-Type ofClass B with one CSI-RS resource) multiplexed with 2-bit HARQ-ACK fornormal cyclic prefix; Format 3a for a first and a second CSI reports(associated respectively with a 1st eMIMO-Type of Class A and a 2ndeMIMO-Type of Class B with one CSI-RS resource) multiplexed with 1-bitHARQ-ACK for normal cyclic prefix; Format 3b for a first and a secondCSI reports (associated respectively with a 1st eMIMO-Type of Class Aand a 2nd eMIMO-Type of Class B with one CSI-RS resource) multiplexedwith 2-bit HARQ-ACK for normal cyclic prefix; and Format 3 for a firstand a second CSI reports (associated respectively with a 1st eMIMO-Typeof Class A and a 2nd eMIMO-Type of Class B with one CSI-RS resource)multiplexed with HARQ-ACK for extended cyclic prefix.

In some embodiments (Set 3), if the UE is configured with aperiodic CSIreporting of 1^(st) and 2^(nd) eMIMO-Types, then it reports the two CSIsaccording to one of the following alternatives: Alt 0: UE reports bothCSI of 1^(st) eMIMO-type and CSI of 2^(nd) eMIMO-type together usingPUSCH Mode 3-2 (Table 27); and Alt 1: UE reports two CSIs separately,wherein, the first CSI of 1^(st) eMIMO-type using PUSCH Mode 0-1 (Error!Reference source not found) and the second CSI of 2^(nd) eMIMO-typeusing PUSCH Mode 3-1 (Table 27).

TABLE 27 CQI and PMI Feedback Types for PUSCH CSI reporting Modes PMIFeedback Type No Single Multiple PMI PMI PMI PUSCH CQI No CQI Mode 0-1Feedback Type Wideband Mode 1-2 (wideband CQI) UE Selected Mode Mode 2-2(subband CQI) 2-0 Higher Layer- Mode Mode 3-1 Mode 3-2 configured 3-0(subband CQI)

In some embodiments, if the UE is configured with aperiodic CSIreporting of 1^(st) eMIMO-Type and periodic CSI reporting of 2^(nd)eMIMO-Type, then it reports the two CSIs as follows: a UE reports theCSI of 1^(st) eMIMO-type using PUSCH Mode 3-2 (Table 27); and a UEreports the CSI of 2^(nd) eMIMO-type using PUCCH Format 2 or 2a or 2b or3 or 3a or 3b.

Although the present disclosure has been described with an exemplaryembodiment, various changes and modifications may be suggested to oneskilled in the art. It is intended that the present disclosure encompasssuch changes and modifications as fall within the scope of the appendedclaims.

None of the description in this application should be read as implyingthat any particular element, step, or function is an essential elementthat must be included in the claims scope. The scope of patented subjectmatter is defined only by the claims. Moreover, none of the claims areintended to invoke 35 U.S.C. §112(f) unless the exact words “means for”are followed by a participle.

What is claimed is:
 1. A user equipment (UE) for communicating in amulti-input multi-output (MIMO) wireless communication system, the UEcomprising: a transceiver configured to receive, from an eNodeB (eNB),periodic CSI feedback configuration information including i) aperiodicity value and an offset value corresponding to a first CSIreport and ii) at least one periodicity value and at least one offsetvalue corresponding to a second CSI report; and at least one processorconfigured to: measure a first CSI reference signal (CSI-RS) and asecond CSI-RS configured for a periodic CSI reporting based on at leasttwo different enhanced MIMO types (eMIMO-Types), the at least twodifferent eMIMO-Types comprising a first eMIMO-Type and a secondeMIMO-Type that are configured with at least two different antenna portconfigurations, respectively; generate the first CSI report and thesecond CSI report for the first eMIMO-Type and the second eMIMO-Type,respectively, using respective codebooks for the first eMIMO-Type andthe second eMIMO-Type, the first CSI report and the second CSI reportbeing associated with the first CSI-RS and the second CSI-RS,respectively; determine a periodic reporting interval for each of thefirst CSI report and the second CSI report, wherein the periodicreporting interval for the first CSI report is determined based on i) atleast one of the periodicity value or the offset value corresponding tothe first CSI report and ii) at least one periodicity value and at leastone offset value corresponding to the second CSI report; and report thefirst and second CSI reports based on the determined periodic reportingintervals using a physical uplink control channel (PUCCH) format 2, aPUCCH format 3, or a combination of the PUCCH format 2 and the PUCCHformat
 3. 2. The UE of claim 1, wherein the at least one processor isfurther configured to: measure the first CSI-RS that is a non-precoded(NP) CSI-RS and the second CSI-RS that is a beamformed (BF) CSI-RS withK=1 resource; generate at least one of a first precoding matrix index(PMI) or a first rank indicator (RI) that is included in the first CSIreport associated with the first eMIMO-Type, wherein the first PMIcomprises at least one of a single PMI or a pair of two PMIs and thefirst eMIMO-Type is Class A; and generate at least one of a second PMI,a second RI, or a channel quality indicator (CQI) that is included inthe second CSI report associated with the second eMIMO-Type, wherein andthe second eMIMO-Type is Class B with K=1 resource.
 3. The UE of claim1, wherein the transceiver is further configured to: jointly report atleast one of a first PMI or a first RI that is included in the first CSIreport; and report each of the first and second CSI reports based on thedetermined periodic reporting interval using the PUCCH format, whereinthe determined periodic reporting interval of the first CSI report isdetermined based on at least one of the periodicity value M_(PMI/RI) orthe offset value N_(OFFSET,PMI/RI) corresponding to the first CSI reportincluded in the periodic CSI feedback configuration information, whereinthe periodicity value M_(PMI/RI) is determined based on at least one ofthe periodicity values M_(RI) and N_(pd) for the second RI, or CQI,respectively, and wherein the offset value N_(OFFSET,PMI/RI) isdetermined based on at least one of the offset values N_(OFFSET,CQI) andN_(OFFSET,RI) for the CQI or the second RI, respectively.
 4. The UE ofclaim 3, wherein the transceiver is further configured to: jointlyreport wideband first PMI and first RI included in the first CSI reportin subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,PMI/RI))mod(n_(pd)·M_(RI)·M_(PMI/RI))=0if a number of antenna ports associated with the second eMIMO-Type ismore than 1 and(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,PMI/RI))mod(N_(pd)·M_(PMI/RI))=0if the number of antenna ports associated with the second eMIMO-Typeis
 1. 5. The UE of claim 1, wherein the transceiver is furtherconfigured to: separately report first PMI and first RI that areincluded in the first CSI report; and report each of the first andsecond CSI reports based on the determined periodic reporting intervalusing the PUCCH format, wherein each of the periodic reporting intervalsfor first PMI and first RI, respectively, is determined based on the atleast one of the periodicity value or the offset value included in theperiodic CSI feedback configuration information, wherein each of theperiodicity values for the first PMI and the first RI, respectively, isdetermined either based on one another or at least one of the second RIor CQI, and wherein each of the offset values for the first PMI and thefirst RI, respectively, is determined either based on one another oreither CQI or the CQI and the second RI.
 6. The UE of claim 1, whereinthe transceiver is further configured to at least one of: report atleast one of the first or second CSI report using at least one of aphysical uplink shared channel (PUSCH) Mode 0-1 or a PUSCH Mode 3-1based on aperiodic CSI feedback configuration information; or reportboth of the first and second CSI reports using a PUCCH Mode 3-2 based onthe aperiodic CSI feedback configuration information, wherein, theaperiodic CSI feedback configuration information for an aperiodic CSIreporting is received from the eNB.
 7. The UE of claim 1, wherein the atleast one processor is further configured to measure the first CSI-RSfor the first CSI report based on the first eMIMO-Type generated using asubset of antenna ports, and wherein the first CSI-RS comprises an NPCSI-RS.
 8. An eNodeB (eNB) for communicating in a multi-inputmulti-output (MIMO) wireless communication system, the eNB comprising:at least one processor configured to: determine a first CSI referencesignal (CSI-RS) and a second CSI-RS configured for a periodic CSIreporting based on at least two different enhanced MIMO types(eMIMO-Types), the at least two different eMIMO-Types comprising a firsteMIMO-Type and a second eMIMO-Type that are configured with at least twodifferent antenna port configurations, respectively; and determine aperiodic reporting interval for each of a first CSI report and a secondCSI report, wherein the periodic reporting interval for the first CSIreport is determined based on i) at least one of a periodicity value oran offset value corresponding to the first CSI report and ii) at leastone periodicity value and at least one offset value corresponding to thesecond CSI report; and a transceiver configured to: transmit, to userequipment (UE), periodic CSI feedback configuration informationincluding i) a periodicity value and an offset value corresponding to afirst CSI report ii) and at least one periodicity value and at least oneoffset value corresponding to a second CSI report; and receive, from theUE, the first and second CSI reports based on the determined periodicreporting intervals using a physical uplink control channel (PUCCH)format 2, a PUCCH format 3, or a combination of the PUCCH format 2 andthe PUCCH format 3, wherein the first CSI report and the second CSIreport are generated for the first eMIMO-Type and the second eMIMO-Type,respectively, using respective codebooks for the first eMIMO-Type andthe second eMIMO-Type, the first CSI report and the second CSI reportbeing associated with the first CSI-RS and the second CSI-RS,respectively.
 9. The eNB of claim 8, wherein: the at least one processoris further configured to: determine the first CSI-RS that is anon-precoded (NP) CSI-RS and the second CSI-RS that is a beamformed (BF)CSI-RS with K=1 resource; and the transceiver is further configured to:receive the first CSI report associated with the first eMIMO-Type,wherein the first CSI report includes at least one of a first precodingmatrix index (PMI) or a first rank indicator (RI), and wherein the firstPMI comprises at least one of a single PMI or a pair of two PMIs and thefirst eMIMO-Type is Class A; and receive the second CSI reportassociated with the second eMIMO-Type, wherein the second CSI reportincludes at least one of a second PMI, a second RI, or a channel qualityindicator (CQI), and wherein and the second eMIMO-Type is Class B withK=1 resource.
 10. The eNB of claim 8, wherein the transceiver is furtherconfigured to: jointly receive at least one of a first PMI or a first RIthat is included in the first CSI report; and receive each of the firstand second CSI reports based on the determined periodic reportinginterval using the PUCCH format, wherein the determined periodicreporting interval of the first CSI report is determined based on atleast one of the periodicity value M_(PMI/RI) or the offset valueN_(OFFSET,PMI/RI) corresponding to the first CSI report included in theperiodic CSI feedback configuration information, wherein the periodicityvalue M_(PMI/RI) is determined based on at least one of the periodicityvalues M_(RI) and N_(pd) for the second RI, or CQI, respectively, andwherein the offset value N_(OFFSET,PMI/RI) is determined based on atleast one of the offset values N_(OFFSET,CQI) and N_(OFFSET,RI) for theCQI or the second RI, respectively.
 11. The eNB of claim 10, wherein thetransceiver is further configured to: jointly receive wideband first PMIand first RI included in the first CSI report in subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,PMI/RI))mod(n_(pd)·M_(RI)·M_(PMI/RI))=0if a number of antenna ports associated with the second eMIMO-Type ismore than 1 and(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,PMI/RI))mod(N_(pd)·M_(PMI/RI))=0if the number of antenna ports associated with the second eMIMO-Typeis
 1. 12. The eNB of claim 8, wherein the transceiver is furtherconfigured to: separately receive first PMI and first RI that areincluded in the first CSI report; and receive each of the first andsecond CSI reports based on the determined periodic reporting intervalusing the PUCCH format, wherein each of the periodic reporting intervalsfor first PMI and first RI, respectively, is determined based on the atleast one of the periodicity value or the offset value included in theperiodic CSI feedback configuration information, wherein each of theperiodicity values for the first PMI and the first RI, respectively, isdetermined either based on one another or at least one of the second RIor CQI, and wherein each of the offset values for the first PMI and thefirst RI, respectively, is determined either based on one another oreither CQI or the CQI and the second RI.
 13. The eNB of claim 8, whereinthe transceiver is further configured to at least one of: receive atleast one of the first or second CSI report using at least one of aphysical uplink shared channel (PUSCH) Mode 0-1 or a PUSCH Mode 3-1based on aperiodic CSI feedback configuration information; or receiveboth of the first and second CSI reports using a PUCCH Mode 3-2 based onthe aperiodic CSI feedback configuration information, wherein, theaperiodic CSI feedback configuration information for an aperiodic CSIreporting is received from the eNB.
 14. A method for communicating in amulti-input multi-output (MIMO) wireless communication system, themethod comprising: receiving, from an eNodeB (eNB), periodic CSIfeedback configuration information including i) a periodicity value andan offset value corresponding to a first CSI report and ii) at least oneperiodicity value and at least one offset value corresponding to asecond CSI report; measuring a first CSI reference signal (CSI-RS) and asecond CSI-RS configured for a periodic CSI reporting based on at leasttwo different enhanced MIMO types (eMIMO-Types), the at least twodifferent eMIMO-Types comprising a first eMIMO-Type and a secondeMIMO-Type that are configured with at least two different antenna portconfigurations, respectively; generating the first CSI report and thesecond CSI report for the first eMIMO-Type and the second eMIMO-Type,respectively, using respective codebooks for the first eMIMO-Type andthe second eMIMO-Type, the first CSI report and the second CSI reportbeing associated with the first CSI-RS and the second CSI-RS,respectively; determining a periodic reporting interval for each of thefirst CSI report and the second CSI report, wherein the periodicreporting interval for the first CSI report is determined based on i) atleast one of the periodicity value or the offset value corresponding tothe first CSI report ii) and at least one periodicity value and at leastone offset value corresponding to the second CSI report; and reportingthe first and second CSI reports based on the determined periodicreporting intervals using a physical uplink control channel (PUCCH)format 2, a PUCCH format 3, or a combination of the PUCCH format 2 andthe PUCCH format
 3. 15. The method of claim 14, further comprising:measuring the first CSI-RS that is a non-precoded (NP) CSI-RS and thesecond CSI-RS that is a beamformed (BF) CSI-RS with K=1 resource;generating at least one of a first precoding matrix index (PMI) or afirst rank indicator (RI) that is included in the first CSI reportassociated with the first eMIMO-Type, wherein the first PMI comprises atleast one of a single PMI or a pair of two PMIs and the first eMIMO-Typeis Class A; and generating at least one of a second PMI, a second RI, ora channel quality indicator (CQI) that are included in the second CSIreport associated with the second eMIMO-Type, wherein and the secondeMIMO-Type is Class B with K=1 resource.
 16. The method of claim 14,further comprising: jointly reporting at least one of a first PMI or afirst RI that is included in the first CSI report; and reporting each ofthe first and second CSI reports based on the determined periodicreporting interval using the PUCCH format, wherein the determinedperiodic reporting interval of the first CSI report is determined basedon at least one or both of the periodicity value M_(PMI/RI) and theoffset value N_(OFFSET,PMI/RI) corresponding to the first CSI reportincluded in the periodic CSI feedback configuration information, whereinthe periodicity value M_(PMI/RI) is determined based on at least one ofthe periodicity values M_(RI) and N_(pd) for the second RI, or CQI,respectively, and wherein the offset value N_(OFFSET,PMI/RI) isdetermined based on at least one of the offset values N_(OFFSET,CQI) andN_(OFFSET,RI) for the CQI or the second RI, respectively.
 17. The methodof claim 16, further comprising: jointly reporting wideband first PMIand first RI included in the first CSI report in subframes satisfying(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,RI)−N_(OFFSET,PMI/RI))mod(n_(pd)·M_(RI)·M_(PMI/RI))=0if a number of antenna ports associated with the second eMIMO-Type ismore than 1 and(10×n_(f)+└n_(s)/2┘−N_(OFFSET,CQI)−N_(OFFSET,PMI/RI))mod(N_(pd)·M_(PMI/RI))=0if the number of antenna ports associated with the second eMIMO-Typeis
 1. 18. The method of claim 14, further comprising: separatelyreporting first PMI and first RI that are included in the first CSIreport; and reporting each of the first and second CSI reports based onthe determined periodic reporting interval using the PUCCH format,wherein each of the periodic reporting intervals for first PMI and firstRI, respectively, is determined based on the at least one of theperiodicity value or the offset value included in the periodic CSIfeedback configuration information, wherein each of the periodicityvalues for the first PMI and the first RI, respectively, is determinedeither based on one another or at least one of the second RI or CQI, andwherein each of the offset values for the first PMI and the first RI,respectively, is determined either based on one another or either CQI orthe CQI and the second RI.
 19. The method of claim 14, furthercomprising: reporting at least one of the first or second CSI reportusing at least one of a physical uplink shared channel (PUSCH) Mode 0-1or a PUSCH Mode 3-1 based on aperiodic CSI feedback configurationinformation; or reporting both of the first and second CSI reports usinga PUCCH Mode 3-2 based on the aperiodic CSI feedback configurationinformation, wherein, the aperiodic CSI feedback configurationinformation for an aperiodic CSI reporting is received from the eNB. 20.The method of claim 14, further comprising measuring the first CSI-RSfor the first CSI report based on the first eMIMO-Type generated using asubset of antenna ports, and wherein the first CSI-RS comprises an NPCSI-RS.